ELECTRIC SWITCH FOR DISCONNECTING A POWER PATH

Abstract

The present invention relates to an electrical switch (100) for opening a current path (102). The switch (100) has a feed line (108) having an opening point (112) for opening the current path (102). At the opening point (112), a switching element (114) movable at least on one side is arranged in the feed line (108) in order to open and / or close the opening point (112). In a closed position, the switching element (114) has, on a movable side, a point of contact (118) with the feed line (108). The switch (100) also has a return line (110), which is electrically connected to the feed line (108) at an end of the feed line (108). A spaced arrangement of the feed line (108) and the return line (110) substantially antiparallel to each other, at least in the region of the opening point (112), is designed to at least partially compensate, by means of a Lorentz force (124) acting on the switching element (114) from the return line (110), a force which, while the current path (102) is carrying current, acts on the switching element (114) as a result of a local Lorentz force in the feed line (108) and in the switching element (114) and / or as a result of a constriction force (122) in the point of contact (118).

Description

[0001] ELECTRIC SWITCH FOR DISCONNECTING A POWER PATH

[0002] Technical field

[0003] The present invention relates to an electrical switch for disconnecting a current path, in particular in high-voltage current paths in a motor vehicle electrical system.

[0004] State of the art

[0005] The present invention is described below primarily in connection with switching elements for vehicle electrical systems. However, the invention can be used in any application where electrical loads are switched.

[0006] For example, if a high current flows through a switch in a vehicle electrical system in the event of a short circuit in a drive system, a contact point may be unintentionally opened by a Lorentz force and / or clamping force in the contact point caused by the current flow.

[0007] When the contact point opens during a high current flow, a switching arc forms at the separation point between the two previously connected ends of the switch. This switching arc releases a large amount of energy, which can damage the switch.

[0008] To prevent such damage, it is best to avoid unintentionally opening a switch operating with a high current flow. Additionally, efforts should be made to reduce the duration of the switching arc, for example, by increasing the voltage drop across the arc beyond the available electrical voltage between its ends. This voltage drop can be increased by lengthening the switching arc. This can be achieved, for instance, by using an air or gas flow to deflect the arc. This lengthens the arc and increases the voltage drop to such an extent that the arc extinguishes.

[0009] Description of the invention

[0010] One object of the invention is to provide a reliably switching electrical switch for disconnecting a current path using the simplest possible means in terms of construction.

[0011] The problem is solved by the subject matter of the independent claim. Advantageous embodiments of the invention are specified in the dependent claims, the description, and the accompanying figures.

[0012] An electrical switch for disconnecting a current path is presented, wherein the switch has a forward conductor with a disconnect point for disconnecting the current path, wherein at the disconnect point a switching element movable on at least one side for opening and / or closing the disconnect point is arranged in the forward conductor, wherein the switching element has a contact point to the forward conductor on a movable side in a closed position, wherein the switch further comprises a return conductor electrically connected to the forward conductor at one end of the forward conductor, wherein a substantially antiparallel spaced arrangement of forward conductor and return conductor is designed at least in the area of ​​the disconnect point toto at least partially compensate a force acting on the switching element due to a local Lorentz force in the forward conductor and the switching element and / or a clamping force in the contact point by a Lorentz force acting on the switching element from the return conductor.

[0013] A current path can be understood as a continuous electrically conductive path between a power source and a load. The power source could be, for example, the traction battery of an electric vehicle. The load could be, for example, the electric vehicle's drive motor. A switch can open and interrupt, or disconnect, the current path. The switch can be integrated into the current path using electrical interfaces. These interfaces can be called terminals. Electrical conductors with a large cross-section can be connected to the terminals. Within the switch, the current path can be formed by busbars. Busbars can be solid strips of electrically conductive material. A conductor can run from an input interface of the switch into the switch housing.A return path can lead from the switch housing to an output interface of the switch. At one end of the forward path opposite the input interface, the forward path can be electrically connected to the return path. The return path can run essentially antiparallel to the forward path back to the output interface.

[0014] When current flows through the outgoing and return conductors, the current flows in opposite or antiparallel directions. Electromagnetic forces caused by the current flow, particularly forces acting on the switching element, such as the Lorentz force and / or the helical force, are also a factor. ' The opposing forces essentially cancel each other out due to the opposing current flow.

[0015] A disconnect point can be a location on the supply line designed to break the current path. The return line can run parallel to the supply line within the switch housing in the area of ​​the disconnect point. The return line can be positioned at a constant distance from the supply line. The distance between the supply and return lines influences the compensating Lorentz force. This distance can be selected according to the expected current intensity on the current path.

[0016] The switch can be designed for repeated opening and closing. The switching element can be designed to open and / or close the disconnect point. The switch can include an actuator for driving the switching element. The switching element can be designed as a bidirectional movable switching bridge. In this case, the switching element can extend parallel to the return line and be moved in a direction perpendicular to the return line, either towards or away from the supply line. Both ends of the switching element are movable, preferably in a direction perpendicular to the direction of extension of the supply line. Alternatively, the switching element can be fixed to the supply line on one side as a switching tongue. The other side of the switching tongue can be movable. The switching element can be connected to the supply line via a hinge. The switching element can also be a movable end of the supply line.

[0017] The switching element can be moved between a closed and an open position. In the closed position, the current path at the contact point is closed. In the open position, the current path is broken. The movable end of the switching element can rest laterally against the end of the supply line in the closed position.

[0018] The length of the switching element in its direction of extension and the distance between the switching element and the return conductor in a direction perpendicular to the direction of extension of the switching element can be dimensioned such that the force acting on the switching element at the contact point due to the local Lorentz force and / or the clamping force is compensated by at least 50% by the Lorentz force caused in the return conductor when the current-carrying current path is active, provided the current flowing through the current-carrying current path is within the current strength for which the switch is designed. Alternatively, the acting force can be compensated by at least 70%, at least 90%, completely, or even overcompensated.

[0019] By compensating, at least to a significant extent, the forces acting as levitation forces (i.e., lifting forces on the switching element), such as the local Lorentz force and / or the Holm narrowing force, with the Lorentz force generated by the return path, the risk of the switch opening unintentionally at high currents and potentially being damaged by arcing can be reduced.

[0020] The switching element can be detachably connected to the supply line at the contact point on the side facing the return line. By being connected on the side facing the return line, the switching element can be pressed against the supply line by the Lorentz force acting on it from the return line. Thus, the clamping force, or the local Lorentz force, between the supply line and the switching element and the Lorentz force acting on the switching element from the return line act in opposite directions. The switching element can be movable into a gap between the supply and return lines to open the disconnect point. By opening it into this gap, the switching element can be pressed against the supply line by the Lorentz force of the return line. In this way, the Lorentz force of the return line can compensate for the local Lorentz force and / or the clamping force.

[0021] The switch can include an actuator for moving the switching element towards and / or away from the contact point. In other words, the actuator can actively move the switching element between the open and closed positions. A spring force stored in a spring accumulator of the actuator can be used for moving the element towards or away from the contact point. The actuator can act against the spring force to move the element towards or away from the contact point. The switching element itself can act as a spring element that keeps the contact point closed or open. When moving the switching element from a rest position, it can be elastically deformed.

[0022] The switching element can be designed as a bidirectional movable switching bridge. The switching bridge can be oriented essentially parallel to the return conductor. The switching bridge can have a contact point at each of its opposite ends. Due to the essentially parallel orientation, the Lorentz force from the return conductor can act essentially entirely on the switching element.

[0023] The switch may include an arc-quenching device for extinguishing the switching arc resulting from the disconnection of the live break point. The arc-quenching device may include a normally de-energized fuse element in a secondary path to the live path. The fuse element may be connected between a terminal on a first side of the break point and a secondary electrode of the secondary path. The secondary electrode may be located on a second side of the break point and be electrically isolated from the live path during normal operation. The secondary path may have a lower electrical resistance than the switching arc. The secondary electrode may be located in an area ionized by the switching arc. This allows the electrical current to commutate to the secondary electrode and flow through the fuse element to the other side of the break point.The safety device can activate when the current flow exceeds its tripping threshold. This safety device could be, for example, a fuse. In a fuse, an arc ignites when the tripping threshold is exceeded. This arc is then extinguished by melting sand within the fuse. By the time the safety device trips, the previous path of the arc has been deionized, preventing the arc from reigniting.

[0024] The secondary electrode can be connected to at least one prong of a quenching comb located adjacent to the junction. The at least two prongs of the quenching comb can be substantially parallel to each other, electrically isolated from one another, and distributed across the opening width of the junction. A quenching comb can have multiple prongs. The prongs can be of different lengths. For example, the outer prongs of the quenching comb can be longer than the inner prongs. The switching arc can jump to the quenching comb because the path across the quenching comb has lower electrical resistance than the original switching arc. The switching arc can be split into several partial arcs within the quenching comb. These partial arcs can migrate into the quenching comb. The secondary electrode can, in particular, be connected to a central prong of the quenching comb.The middle prong can be the shortest prong. The secondary electrode can provide a path for current flow through the switching arc that offers less resistance than a path around the secondary electrode or through the remaining prongs. The current flows along the path of least resistance. Once the current flow through the secondary path is established, the cut-off partial arcs extinguish. Subsequently, the fuse element in the secondary path completely interrupts the current flow.

[0025] The tines of the quenching comb can be designed as plates that are essentially parallel to each other. A leading edge of the plates can be positioned at a distance from the current path in the area of ​​the break. Essentially, the leading edge can be aligned parallel to the current path. Plate-shaped tines allow the partial arcs to travel across a surface of the plates and move away from each other. This makes it more difficult for extinguished partial arcs to reignite.

[0026] The switch may have at least one blow-out magnet. The blow-out magnet may be located adjacent to the break point. The blow-out magnet may be designed to deflect the switching arc away from the break point. A blow-out magnet may be a permanent magnet or an electromagnet. The blow-out magnet may be divided into several sub-magnets. Sub-magnets may mutually reinforce and / or homogenize their magnetic fields. The blow-out magnet may be oriented such that its magnetic field is essentially homogeneous in the region of the break point. The magnetic field deflects the charge carriers and ionized particles moved by the current flow through the switching arc laterally in the region of the switching arc. This deflection increases the length of the switching arc and thus increases the voltage drop in the switching arc. The blow-out magnet may deflect the switching arc toward the secondary electrode.When using a blow-out magnet, the field strength of the magnetic field in the area of ​​the switching element can be taken into account when determining the distance between the outgoing and return lines.

[0027] The switch can include a movable, electrically insulating element that can be inserted into the open disconnect point, and an actuator for moving the element. The element can be a molded part with cutouts for the components of the disconnect point.

[0028] The element can essentially enclose the components. This enclosing action significantly increases the distance that the switching arc must bridge. This prevents a new switching arc from being reignited. Additionally, the components of the disconnect point are fixed within the cutouts, ensuring that the open state of the disconnect point remains secure even under vibration.

[0029] Brief character description

[0030] An advantageous embodiment of the invention is explained below with reference to the accompanying figures. These show:

[0031] Fig. 1 shows a representation of a switch according to an exemplary embodiment;

[0032] Figs. 2a to 2c show illustrations of a switch with a slide-in element according to an exemplary embodiment;

[0033] Fig. 3 shows a switch with a quenching device according to an embodiment; Figs. 4a and 4b show the quenching of a switching arc at a switch according to an embodiment;

[0034] Fig. 5 shows a switch with a cutting wedge and a quenching device; and

[0035] Figs. 6a and 6b show the extinguishing of a switching arc at a switch using a cutting wedge.

[0036] The figures are merely schematic representations and serve only to illustrate the invention. Identical or equivalent elements are consistently identified by the same reference numerals.

[0037] Detailed description

[0038] For ease of understanding, the reference symbols to Figures 1-6 will be retained in the following description.

[0039] Fig. 1 shows a representation of a switch 100 according to an exemplary embodiment. The switch 100 is designed to repeatedly open and close a current path 102. The switch is designed for switching automotive high-voltage voltages with correspondingly high electrical current flows and therefore has appropriately large conductor cross-sections made of electrically conductive material, adapted material thicknesses of electrically insulating material, and the necessary clearances and creepage distances. Automotive high-voltage voltages can reach up to one kilovolt. For example, the voltage in the high-voltage vehicle electrical system can be between 400 and 600 V or between 800 and 1000 V. Particularly in the event of a short circuit, high currents can flow. For example, the maximum short-circuit current can be up to 15 kA. Depending on the internal resistance of the battery, the short-circuit current can reach up to 30 kA.

[0040] Switch 100 has a first terminal 104 as an input interface and a second terminal 106 as an output interface. Terminals 104 and 106 are located on the same side of switch 100 because switch 100 has a forward line 108 from the first terminal 104 into switch 100 and a return line 110 running parallel to it from switch 100 back to the second terminal 106. The forward line 108 and the return line 110 thus run through switch 100 at a constant distance within a narrow tolerance range. The forward line 108 and the return line 110 are electrically connected to each other on the side facing away from terminals 104 and 106.

[0041] Terminals 104 and 106 are configured here as extensions of the supply line 108 and the return line 110, respectively. The supply line 108, the return line 110, and the connection between the two are designed as solid busbars made of electrically conductive material, such as copper. Terminals 104 and 106 each have an opening for a connecting element to link the switch 100 to the current path.

[0042] A disconnect point 112 of the switch 100 is arranged in the supply line 108. Here, the disconnect point 112 is formed by a switching element 114 that is movable on both sides. The switching element 114 is mechanically coupled to an actuator 116. The switching element 114 is designed as a solid switching bridge and has contact surfaces 118 at two opposite end regions, with which the switching element bears against the free ends of the supply line 108. The switching bridge has essentially the same conductor cross-section as the supply line 108.

[0043] The switching element 114 is arranged here in a space 120 between the supply line 108 and the return line 110. To disconnect the disconnect point 112, the switching element 114 is moved further away from the supply line 108 into the space 120. The contact surfaces 118 are designed as contact plates to achieve increased surface pressure for a suitable electrical contact and / or low contact resistance between the switching element 114 and the supply line 108 when the switch 100 is closed.

[0044] When switch 100 is closed, the current path 102 is closed, and current can flow through switch 100. This current flow results in a local Lorentz force and / or clamping force 122 at the contact points 118, which tends to lift the switching element 114 away from the outgoing conductor 108. The current flowing in the opposite direction through the parallel return conductor 110 also generates a Lorentz force 124, which is directed opposite to the Lorentz force and / or clamping force 122. The Lorentz force 124 and the Lorentz force and / or clamping force 122 essentially cancel each other out. The Lorentz force 124 depends primarily on the current in the return conductor 110 and the distance between the outgoing conductor 108 and the return conductor 110.

[0045] In one embodiment, two blow-out magnets 126 are arranged in the space 120. The blow-out magnets 126 are arranged to the right and left of the switching element 114.

[0046] The blow-out magnets 126 are aligned such that their magnetic fields reinforce each other in the area of ​​the switching element 114. The north pole of one blow-out magnet 126 points towards the south pole of the other blow-out magnet 126. This also results in a homogeneous magnetic field between the blow-out magnets 126.

[0047] Figures 2a to 2c show illustrations of a switch 100 with a slide-in element 200 according to an exemplary embodiment. The switch essentially corresponds to the switch in Figure 1. The illustration in Figure 2a essentially corresponds to the illustration in Figure 1. In contrast, the switch 100 is shown with the disconnect point 112 open.

[0048] The switching element 114 has been drawn into the gap 128 by the actuator 116. The contact points 118 are non-contact. The element 200 has been inserted into the open separation point 112 from the side by a further actuator (not shown). The element 200 is made of an electrically insulating material, for example, a ceramic material. In the illustrated embodiment, no blow-out magnet is used in order not to influence the compensating Lorentz force.

[0049] In Fig. 2b, the element 200 with recesses 202 for the ends of the supply line 108 and the switching element 114 is shown. The contact plates of the contact points 118 are also shown in the recesses 202. In Fig. 2a, the ends and the switching element 114 are arranged in the recesses 202. The recesses ensure a relative position of the switching element 114 to the supply line 108 and prevent accidental closing of the disconnect point 112 by the element 200 located in the disconnect point 112. The element 200 ensures that the switch 100 remains open even if the switch 100 is subjected to strong vibrations and / or the actuator 116 fails. In Fig. 2c, the further actuator 204 is shown. Here, the other actuator 204 is in the process of inserting the element 200 into the opened separation point 112.

[0050] In other words, Figures 1 and 2 show a switch with compensation for levitation force. This relates to the interaction between a high-voltage contactor and a high-voltage fuse in high-voltage switchgear boxes of electric and hybrid vehicles (BEV & PHEV).

[0051] In the case of large short-circuit currents, the contactor should remain closed, and a fuse, especially one connected in series with the contactor, should interrupt the current. However, if the contactor's electromagnetic forces, particularly the Lorentz force and Holm's limiting force, cause the contacts to open unintentionally before the fuse trips, the contactor can explode. Furthermore, the arcs that then form in the contactor limit the short-circuit current due to their voltage drop, which delays the fuse from tripping. The fuse trips when its melting integral (I) 2 t-value) is reached.

[0052] The current flow geometry presented here compensates for the Lorentz force and the contact force. As a result, only the desired contact force generated by a spring is effective. Additionally, the resulting arc can be extinguished by inserting an electrical insulator, for example, made of ceramic.

[0053] Arc extinguishing magnets can be used to extinguish the electric arc. These generate a magnetic field oriented perpendicular to the direction of electron movement in the arc, deflecting the electrons into a circular path. This lengthens the arc path, which is proportional to the arc voltage. Arc extinguishing magnets can also generate an additional Lorentz force acting on the switching bridge, thereby reducing the levitation threshold at which the switching contacts lift off.

[0054] The approach presented here increases system safety because the contactor remains in a closed state, does not explode, but is at most welded shut. A series-connected fuse with a higher fuse rating can be used, as the contactor's robustness is increased. This allows it to handle the likely future increase in charging currents. The switch presented here exhibits significantly higher levitation limits compared to known contactors, without substantially increasing the component size. For example, a levitation limit of more than eight kiloamperes can be achieved.

[0055] In the switch presented here, the busbars are arranged so that the Lorentz force on the switching bridge, caused by the additional lower busbar, presses it against the bridge. The lower busbar is spaced precisely so that the electromagnetic forces cancel each other out. The compensating Lorentz force can be...

[0056] F L = B(l, d) x L * I can be described with the current I, the vector length of the switching bridge L and the magnetic flux density B(l, d) at the location of the switching bridge, which depends on the current and the distance d to the lower busbar.

[0057] By appropriately choosing the parameters d and L, the external Lorentz force can be adjusted so that it compensates for the local Lorentz and tightening forces at the two contact points.

[0058] To extinguish the arc that forms when contacts are opened under current, magnets can be used. Due to their magnetic field direction, which is perpendicular to the direction of charge carrier movement, these magnets force the electrons into a circular path. This increases the arc length until the arc finally breaks. However, the magnetic field of the magnets also penetrates the switching bridge, thus intensifying the repulsive Lorentz force.

[0059] To avoid this, the switch in Fig. 2 does not have blow-out magnets. The arc is extinguished by inserting a body made of an electrical insulator (e.g., ceramic). This penetrates the contact point and then greatly extends the arc until it breaks.

[0060] Fig. 3 shows a representation of a switch 100 with a quenching device 300 according to an exemplary embodiment. The switch 100 essentially corresponds to the switch in Figures 1 and 2. In addition, the switch 100, as the quenching device 300, has a secondary path 302 to the current path 102 that is normally de-energized. A fuse element 304 is arranged in the secondary path 302. The fuse element 304 is a cartridge fuse. A first end of the fuse element 304 is electrically connected to the current path 102 on a first side of the disconnect point 112. A second end of the fuse element 304 is electrically connected to a secondary electrode 306. The secondary electrode 306 is electrically insulated from the current path 102 during normal operation. Here, the secondary electrode 306 is arranged laterally next to the disconnect point 112.

[0061] In one embodiment, the secondary electrode 306 is connected to a central prong 308 of an extinguishing comb 310. The extinguishing comb 310 has five prongs 308, which are arranged distributed across the opening width of the separation point 112. The prongs 308 are electrically insulated from one another. The outer prongs 308 of the extinguishing comb 310 are longer than the inner prongs 308. The central prong 308 is the shortest prong 308 and thus furthest from the separation point 112.

[0062] In one embodiment, the secondary electrode 306 is connected to the return conductor 110 via the locking element 304, thus shortening the secondary path 302. Here, a single blow-out magnet 126 is arranged laterally next to the disconnect point 112. As a result, the magnetic field lines run in an arc through the disconnect point 112. However, the blow-out magnet 126 is significantly longer than the switching element 114, so that the magnetic field in the region of the disconnect point 112 is essentially homogeneous.

[0063] In one embodiment, the tines 308 of the extinguishing comb 310 are designed as plates. The plates are oriented essentially parallel to each other. Each of the plates has a substantially constant distance to the current path 102.

[0064] In other words, the switch 100 shown here has a lead line 108 with a disconnect point 112 for disconnecting a current path 102, wherein a switching element 114, movable at least on one side, is arranged at the disconnect point 112 for opening and / or closing the disconnect point 112 in the lead line 108, wherein the switching element 114 has a contact point 118 to the lead line 108 in a closed position on a movable side, wherein the switch 100 has a quenching device 300 for quenching a switching arc resulting from the disconnection of the current-carrying disconnect point 112, wherein the quenching device 300 has a normally de-energized fuse element 304 in a secondary path 302 to the current path 102, wherein the fuse element 304 is connected between a connection to a first side of the disconnect point 112 and a secondary electrode 306 of the secondary path 302.wherein the secondary electrode 306 is arranged in the region of a second side of the disconnect point 112 and is electrically isolated from the current path 102 during normal operation, wherein the switch 100 further comprises an extinguishing comb arranged adjacent to the disconnect point 112 with at least two prongs 308, wherein the prongs 308 may be substantially parallel to each other, are electrically isolated from each other and are arranged distributed over an opening width of the disconnect point 112, wherein the secondary electrode 306 is connected to at least one of the prongs 308.

[0065] Figures 4a and 4b show illustrations of the extinguishing of a switching arc 400 at a switch 100 according to an exemplary embodiment. The switch 100 essentially corresponds to the switch in Figure 3. In Figure 4a, the switch 100 has just been opened using the actuator (not shown). At the contact point 118, the switching arc 400 has ignited between the supply line 108 and the switching element 114. The blow-out magnet 126 has blown the switching arc 400 into the extinguishing comb 310. This has caused the switching arc 400 to divide into five partial arcs 402. The partial arcs 402 run from the supply line 108 to the nearest prong 308, from there from prong 308 to prong 308, skipping the shortest, middle prong 308, and from the last prong 308 to the switching element 114. In each partial arc 402, voltage drops and weakens the switching arc 400.

[0066] In Fig. 4b, the switching arc 400 has jumped to the middle prong 308 and thus to the secondary electrode 306, since the electrical potential of the return line 110 is directly applied to the secondary electrode 306. The partial arcs 402 to the other prongs 308 have extinguished. Due to the flashover to the secondary electrode 306, the current flow in the secondary path 302 exceeds a response threshold of the fuse element 304 and it trips. The tripped fuse element 304 interrupts the current flow, the switching arc 400 extinguishes, and the disconnect point 112 is disconnected.

[0067] In other words, Figures 3 and 4 show a switch with an arc-quenching device integrated into an arc-quenching comb. The contactor presented here can interrupt larger short-circuit currents. The arc-quenching device is used to extinguish the arc. The arc-quenching device is integrated into a so-called arc-quenching comb. The principle of such a comb is based on the effect of arc lengthening and the initial voltage drop of an arc of approximately 10 to 20 V. An airflow or magnets drive the arc into the arc-quenching comb. The secondary electrode of the arc-quenching device is located in the rear part of the arc-quenching comb. This can also be implemented as a connection to a lamella of the comb. Due to the lower resistance of the secondary path compared to the disturbed primary path across the entire arc-quenching comb, a large portion of the current subsequently flows through this path.In the arc-locking safety element, the current melts a constriction, creating an arc within the element. This arc is then extinguished by the safety element, which may be filled with sand, for example. This interrupts the path and provides galvanic isolation.

[0068] In one embodiment, the switch features the special busbar geometry shown in Fig. 1 to compensate for the levitation effect. Since blow magnets are required for the quenching comb to function, the electromagnetic forces cannot be completely eliminated, but they can be significantly reduced. This significantly increases the levitation limit.

[0069] The approach presented here increases system safety because the contactor can interrupt larger currents via the quenching comb. This eliminates the unsafe condition that can arise from the interaction of the contactor and a fuse connected in series. The underlying reason is that the fuse's tripping time is determined by its characteristic current (I). 2 The t-value is determined. Therefore, the lower the current, the longer the fuse takes to reach its melting point. Since the heating of the constriction is also less adiabatic at lower currents, the tripping time is further extended. If the switching threshold of the contactor can be increased, the tripping time of the fuse is significantly reduced.

[0070] Figure 3 shows the contactor with the arc quenching comb integrated into the quenching comb. A magnet is positioned laterally to the switching chamber. This magnet can also be interrupted, as in Figure 1, so that the arrangement includes two magnets. The blow-out magnet generates a magnetic field in the switching chamber, which is oriented perpendicular to the direction of electron flow in the arc, causing the electrons to be deflected and driven towards the quenching comb. When the blow-out magnets are positioned to the right and left of the switching chamber, a very homogeneous magnetic field is created inside the switching chamber. The blow-out magnets could also be designed as electromagnets.

[0071] In Fig. 4, the deflection of the electrons into a circular path is clearly visible. The action of the comb divides the arc into several parts. Each part results in an initial arc voltage of 10 to 20 V, depending on the comb material, so that the arc voltage is gradually increased. This is sufficient to extinguish the arc in the case of normal overcurrents. The arc breaks shortly after entering the quenching comb, and the current is interrupted. The arc diverter remains inactive in this case.

[0072] At very high short-circuit currents, the "cloud" of ionized gas in the arc comb reaches the secondary electrode of the arc breaker, which is connected to the other potential via an overcurrent protection device. This creates a potential difference between the arc base on the contactor and the secondary electrode. The arc commutates to this secondary electrode, extinguishing the portion of the primary arc that flows to the contactor bridge. Once the melting point of the overcurrent protection device / fuse is reached, an arc ignites within it, subsequently interrupting the current path.

[0073] In one embodiment, the contactor is combined with the arc-stop device in the quenching comb using the levitation force compensation principle shown in Fig. 1. The additional magnetic field of the permanent magnets / blowing magnets influences the Lorentz force independently of the current. The busbars are arranged such that the Lorentz force caused by the conductor loop acts on the switching bridge in a closing manner. The switching bridge moves in the magnetic field of the lower busbar B(l, d) and in the magnetic field of the blowing magnets BL. The following applies to the resulting Lorentz force:

[0074] F L = B(l, d) x L * I + B L x L * I with the current I and the length of the switching bridge L (vectorically). L is defined such that it is positive if the current flows in the L direction. B xxL describes the cross product of the respective magnetic field component and the length of the contact bridge (vector-wise). By appropriately choosing the parameters d and L, the external Lorentz force can be adjusted so that it largely compensates for the local Lorentz and clamping forces at the two contact points. The effect of the blow-out magnets reduces or increases the compensating force depending on the current direction. Since the magnetic field of the blow-out magnets does not depend on the current I, this arrangement can only achieve a balance of the repulsive and compressive electromagnetic forces acting on the switching bridge for a specific current value.

[0075] Fig. 5 shows a representation of a switch 100 with a cutting wedge 500 and a fire suppression device 300. The switch 100 essentially corresponds to the switch in Fig. 3. In contrast, the switch 100 can only be used once to safely disconnect the current path 102 and is destroyed in a controlled manner during this process. Therefore, the switch 100 has no switching element at the disconnection point 112. Instead of a switching element, a solid electrical conductor 502 runs through the disconnection point 112. The cutting wedge 500 is aligned with the disconnection point 112. The switch 100 also has the actuator 116 to drive the cutting wedge 500. In contrast to Fig. 1, the actuator 116 here is an electrically detonated explosive charge. Due to the use of the detonator as the actuator 116, the switch 100 can be called a pyrotechnic fuse and used as a controllable overcurrent protection device.

[0076] As shown in Fig. 3, the extinguishing device 300 has a secondary path 302 which is normally de-energized. The fuse element 304 and the secondary electrode 306 are also arranged in the secondary path 302. The secondary path 302 is connected to the current path 102 on the first side of the disconnect point 112. The secondary electrode 306 is located on the opposite second side of the disconnect point 112, but spaced apart from the current path 102.

[0077] A support 504 for the cutting wedge 500 is arranged between the current path 102 and the secondary path 302. The support 504 is located downstream of the cut point 112 from the perspective of the cutting wedge 500 and is designed to catch the cutting wedge 500 after it has cut through the cut point 112. During this catch-up, the cutting wedge 500 can penetrate the support 504 and become lodged there.

[0078] The conductor 502 has a reduction 506 at the separation point 112. The reduction is a predetermined breaking point of the conductor 502 and has a reduced conductor cross-section. However, the conductor cross-section is still sufficient to transmit the required electrical load.

[0079] The switch 100 has no return path, since no compensation of the Lorentz force or the clamping force is required for the solid continuous conductor 502, or such forces do not occur or are only negligible with the specified switch geometry.

[0080] In other words, the switch 100 shown here, for disconnecting a current path 102 at a disconnect point 112, has an electrical conductor 502 that is destructible at the disconnect point 112. A cutting wedge 500, driven by an actuator 116, is aligned with the disconnect point 112. The switch 100 has a quenching device 300 for extinguishing a switching arc resulting from the disconnection of the current-carrying disconnect point 112. The quenching device 300 has a normally de-energized fuse element 304 in a secondary path 302 to the current path 102. The fuse element 304 is connected between a terminal to a first side of the disconnect point 112 and a secondary electrode 306 of the secondary path 302. The secondary electrode 306 is located in the region of a second side of the disconnect point 112 and is electrically isolated from the current path 102 during normal operation.

[0081] Figures 6a and 6b show illustrations of the extinguishing of a switching arc 400 at a switch 100. The switch 100 essentially corresponds to the switch in Figure 5. In Figure 6a, the detonator has been ignited by an electrical signal from a control unit and has driven the cutting wedge 500 through the conductor 502 at the break point 112. Due to the sudden interruption of the current path, the switching arc 400 is drawn up at the break point 112. Here, the switching arc 400 still burns through a remaining gap 600 between the cutting wedge 500 and the abutment 504, since the cutting wedge 500 has not yet reached the abutment 504 on its trajectory.

[0082] In Fig. 6b, the cutting wedge 500 has reached the abutment 504 and penetrated it. The cutting wedge 500 is now stuck in the abutment 504. This has closed the gap, and the switching arc 400 has commutated to the secondary electrode 306. An electric current now flows through the secondary path 302 of the extinguishing device 300. The current is greater than the tripping threshold of the fuse element 304, and the fuse element trips. Here, the fuse element 304 is a fuse. When the tripping threshold is exceeded, another arc ignites in the fuse, destroying the electrical conductor running through the fuse. The arc melts at least part of the sand filling of the fuse. The molten sand extinguishes the arc, thus interrupting the secondary path 302.

[0083] In other words, Figures 5 and 6 show a Pyrofuse with an arc switch.

[0084] A fuse can be connected in parallel with a Pyrofuse. Due to the different contact resistances of the Pyrofuse and the fuse, the Pyrofuse carries a large portion of the traction or charging current. This reduces the aging of the fuse. Since the fuse carries currents during operation, its rated current must not fall below a certain value, otherwise its aging will accelerate again.

[0085] The Pyrofuse presented here incorporates an "arc diverter." In the event of an overcurrent, the Pyrofuse's explosive charge is detonated by a trigger signal. Subsequently, a shearing wedge, an extinguishing agent, and / or a gas are used to break a busbar with a predetermined breaking point. This creates an electric arc. As the distance between the two busbar segments increases, the arc lengthens, thereby increasing the arc voltage. An extinguishing agent can help cool the arc, which also increases the arc voltage. When the voltage reaches the value of the external supply voltage, the arc is extinguished. For higher currents, an increasingly longer arc length is required to generate the necessary arc voltage.

[0086] The secondary electrode of the arc-fuse, which incorporates a fuse element, is positioned below the busbar. It is arranged so that, during disconnection, a portion of the busbar approaches the secondary electrode. Due to the arc plasma and ionized gases, the secondary arc ignites at a specific moment. Because of the reduced distance between one portion of the busbar and the secondary electrode compared to the other, a large portion of the current now flows through the secondary path. The primary arc can be extinguished by the pyrofuse. The current melts a constriction in the fuse element, creating an arc. This arc is also extinguished by the fuse element, which may be filled with sand, for example. The path is interrupted and galvanically isolated.

[0087] The fuse is never subjected to current during normal vehicle operation. This completely eliminates current-related aging mechanisms. The fuse rating can be significantly reduced, which in turn also considerably reduces the tripping time. The fuse can be smaller because it is used to ensure rapid tripping. The majority of the switching energy is absorbed by the fuse element.

[0088] The Pyrofuse in Fig. 5 has a detonator located in its upper part, which can be ignited by a trigger, for example, an electrical pulse. In the variant shown here, with a wedge instead of extinguishing agent or gas, a disconnecting wedge is located beneath the detonator, which can interrupt a busbar at a predetermined point. During the shutdown process shown in Fig. 6, after the detonator is ignited and the busbar is disconnected by the wedge, an arc is ignited, which the wedge propagates. In other embodiments, the arc is extended towards the secondary electrode by the extinguishing agent or the pressure of the gas.

[0089] The ionized gas of the arc and the decreasing distance between the primary rail and the secondary electrode cause the secondary arc to ignite. The primary rail can also touch the secondary electrode. Since the current can now flow with less resistance through the secondary path, a large portion of it now flows through this path. The primary arc also extinguishes due to the action of the wedge.

[0090] Once the melting point of the overcurrent protection device is reached, another arc ignites within the component. Due to the design of the fuse element, a long arc is quickly established, in which the essential energy conversion, necessary for interrupting the short-circuit current, takes place. At an instantaneous power of up to approximately 1.5 MW, the sand filling melts locally. The molten sand extinguishes the arc, thus interrupting the current flow. Through appropriate timing of the disconnection process, the wedge is positioned within the fuse element sufficiently during the interruption of the current flow to prevent the arc from "jumping back" to the primary path. The arc extinguishes. Subsequently, the current flow is completely interrupted, and the path is galvanically isolated.The principle of diverting the electric arc to a secondary path using energy control is called an arc diverter.

[0091] Since the devices and methods described in detail above are exemplary embodiments, they can usually be modified extensively by a person skilled in the art without departing from the scope of the invention. In particular, the mechanical arrangements and the relative sizes of the individual elements are chosen only as examples.

[0092] REFERENCE MARK LIST

[0093] 100 Switch 102 Current path 104 Terminal 106 Terminal 108 Outgoing line 110 Return line 112 Disconnect point 114 Switching element 116 Actuator 118 Contact surface 120 Gap 122 Clamping force 124 Lorentz force 126 Blow-out magnet

[0094] 200 Element 202 Recess 204 Actuator

[0095] 300 Extinguishing device 302 Secondary path 304 Safety element 306 Secondary electrode 308 Prong 310 Extinguishing comb

[0096] 400 Switching arc 402 Partial arc

[0097] 500 Cutting wedge 502 Conductor 504 Abutment 506 Tapered section 600 Gap

Claims

REQUIREMENTS 1. Electrical switch (100) for disconnecting a current path (102), wherein the switch (100) has a forward conductor (108) with a disconnect point (112) for disconnecting the current path (102), wherein a switching element (114) movable at least on one side is arranged at the disconnect point (112) for opening and / or closing the disconnect point (112) in the forward conductor (108), wherein the switching element (114) has a contact point (118) to the forward conductor (108) on a movable side in a closed position, wherein the switch (100) further comprises a return conductor (110) electrically connected to the forward conductor (108) at one end, wherein a substantially antiparallel spaced arrangement of forward conductor (108) and return conductor (110) is formed at least in the region of the disconnect point (112) toto at least partially compensate a force acting on the switching element (114) in the current-carrying current path (102) due to a local Lorentz force in the forward conductor (108) and the switching element (114) and / or a constriction force (122) in the contact point (118) by a Lorentz force (124) acting on the switching element (114) from the return conductor (110).

2. Switch (100) according to claim 1, wherein a length (L) of the switching element (114) in the extension direction of the switching element (114) and a distance (d) between the switching element (114) and the return line (110) in a direction perpendicular to the extension direction of the switching element (114) are dimensioned such that the force acting on the switching element (114) at the contact point (118) due to the local Lorentz force and / or the constriction force (122) is compensated by the Lorentz force (124) caused in the return line (110) when the current-carrying current path (102) is flowing, at a current intensity (I) flowing through the current-carrying current path (102) for which the switch (100) is designed, is compensated to at least 50%.

3. Switch (100) according to one of the preceding claims, wherein the switching element (114) is detachably connected to the forward line (108) at the contact point (118) on a side directed towards the return line (110).

4. Switch (100) according to one of the preceding claims, wherein the switching element (114) is movable into an intermediate space (120) between the forward line (108) and the return line (110) for opening the disconnect point (112).

5. Switch (100) according to one of the preceding claims, further comprising an actuator (116) for bringing the switching element (114) towards and moving the switching element (114) away from the contact point (118).

6. Switch (100) according to one of the preceding claims, wherein the switching element (114) is designed as a switching bridge movable on both sides, the switching bridge being oriented substantially parallel to the return line (110).

7. Switch (100) according to one of the preceding claims, with a quenching device (300) for quenching a switching arc (400) resulting from the disconnection of the current-carrying disconnect point (112), wherein the quenching device (300) has a normally de-energized fuse element (304) in a secondary path (302) to the current path (102), wherein the fuse element (304) is connected between a connection to a first side of the disconnect point (112) and a secondary electrode (306) of the secondary path (302), wherein the secondary electrode (306) is arranged in the region of a second side of the disconnect point (112) and is electrically isolated from the current path (102) during normal operation.

8. Switch (100) according to claim 7, further comprising a quenching comb arranged adjacent to the separation point (112) with at least two prongs, wherein the prongs (308) are substantially parallel to each other, are electrically separated from each other and are arranged distributed over an opening width of the separation point (112), wherein the secondary electrode (306) is connected to at least one of the prongs (308).

9. Switch (100) according to claim 8, wherein the prongs (308) of the quenching comb (310) are formed as plates that are substantially parallel to each other, wherein a leading edge of the plates is arranged spaced apart from the current path (102) in the area of ​​the separation point (112) and is substantially parallel to the current path (102).

10. Switch (100) according to one of the preceding claims, further comprising at least one blow-out magnet (126) which is arranged adjacent to the separation point (112) and is designed to deflect the switching arc (400) away from the separation point (112).

11. Switch (100) according to one of the preceding claims, further comprising a movable electrically insulating element (200) that can be inserted into the opened separation point (112) and an actuator (204) for moving the element (200).