The subject matter relates to a disconnecting device for a power line, in particular a motor vehicle power line, comprising at least one disconnecting means which is spatially arranged between a first and a second connector when the disconnecting device is in a closed state. Furthermore, the subject matter relates to a method for disconnecting a power line.
The electrical protection of power conductors, in particular motor vehicle power conductors, represents a safety-relevant area of motor vehicle technology with regard to ensuring the safety of the vehicle occupants. In particular motor vehicle power conductors which carry a high current, such as the starter and generator cables, the main battery line and/or additional current-carrying lines of the motor vehicle power supply, must be quickly disconnected from the vehicle battery in the event of accidents. If this is not ensured, short circuits with momentarily very high currents can occur in the event of accidents. The high short-circuit currents can lead to the formation of electric arcs. This must be reliably prevented so that the safety of the vehicle occupants is not at risk.
Nowadays, disconnecting devices in which the power lines are disconnected by pyrotechnic disconnecting devices when there is a threat of a short circuit are frequently used. The disconnection of the power lines by means of the pyrotechnic disconnecting devices is generally achieved either by mechanically cutting the power line or by accelerating a pin out of a cylinder, in the closed state, a current path being formed between the pin and the cylinder, which path is cut by the disconnecting device, e.g. the pin.
In the case of the pyrotechnic disconnecting devices which are conventionally used, it is disadvantageous that at the moment of the disconnection of a current-carrying line, electric arcs can form between the gap at the disconnecting point, as a result of which the connectors remain electrically interconnected at least temporarily. This is often the case in particular for high-voltage applications in electric or hybrid vehicles, since in this case, the formation of electric arcs is particularly favoured as a result of the high currents and differences in potential.
For these reasons, the problem addressed by the subject matter is that of providing a disconnecting device for power lines which ensures safe disconnection of current-carrying lines even in high-voltage applications.
This problem is solved in terms of subject matter by a disconnecting device for a power line, having at least one disconnecting means which is spatially arranged between a first and a second connector when the disconnecting device is in a closed state, the disconnecting means comprising at least one connecting element forming an electrical connection between the connectors when the disconnecting device is in the closed state, wherein the connecting element is electrically connected to the first connector via a first contact point and to the second connector via a second contact point when the disconnecting device is in the closed state, and wherein the disconnecting means is arranged in such a way that a breakdown voltage between the first and the second connector when the disconnecting device is in an open state is greater than between the first connector and the first contact point of the connecting element and/or between the second connector and the second contact point of the connecting element.
In this case, the disconnecting device can be designed in such a way that the first and second connectors are current-carrying components of a motor vehicle power line. Likewise, the first and second connectors can also be current-carrying components of power lines of other vehicles, of building installations, of electrically operated machines or signal boxes. In particular in locations where high currents are flowing, it is expedient to provide concrete protection of the electric circuits. Advantageously, for this purpose, the disconnecting device in the closed state has a current load capacity of more than 10 ampere, preferably of more than 20 ampere, in particular of more than 100 ampere.
Likewise, wherever there are relatively high voltages, it is expedient to provide concrete protection of the electric circuits. To ensure safe disconnection for example even of lines in high-voltage power supplies, the disconnecting device is advantageously formed in such a way that there is a difference in potential of at least 100 V, preferably of at least 200 V, in particular of more than 200 V between the connectors in the open state.
To achieve the most loss-free power supply possible in a closed state of the disconnecting device, the connecting element and the connectors can be formed preferably from an electrically conductive material, such as a copper material or an aluminium material. In this case, the connectors and the connecting element can also be formed from different materials. Advantageously, the material of the connecting element or the connectors can be adapted to the requirements in each case. A copper material is preferably used in the region of the power transmission where only a limited installation space is available and, at the same time, there are high operating temperatures and high mechanical requirements placed on the material. An aluminium material is used in the region of the power transmission wherever weight or costs are to be saved.
The connecting element can preferably be in the form of a flat cable. It is understood that, according to another embodiment, round cables can equally be used instead of flat cables. At the same time, a combination of round and flat cables can also be provided. The cables can be formed from solid material.
It has been recognised that when disconnecting current-carrying lines, it is possible to reduce, in an extremely efficient manner, the probability of electric arcs being formed if a current-carrying line is disconnected substantially simultaneously not only at one, but at two disconnecting points. The induced voltage is thereby divided between both disconnecting points, as a result of which the voltage to be disconnected is divided between the two disconnecting points.
To ensure the most efficient possible reduction in the probability of electric arcs being formed, it is therefore proposed that the connecting element can be arranged on the disconnecting means in such a way that a disconnection takes place at at least two contact points at substantially the same time.
For this purpose, it is proposed that the connecting element can be connected to the disconnecting means at least in an interlocking manner, for example as a tongue-and-groove or dovetail connection. Preferably, the connecting element can be connected to the disconnecting means with a force fit, for example in a wedged or screwed manner. Particularly preferably, the connecting element can be connected to the disconnecting means in an integrally bonded manner, in particular soldered, bonded or welded.
To ensure the most simultaneous possible disconnection of the connectors from the connecting element, it is proposed that the disconnecting device can preferably be formed in such a way that the disconnecting means can be moved translationally and/or rotationally between an open and a closed state of the disconnecting device. In this case, the shape of the disconnecting means can advantageously be adapted to the manner of the disconnection. Thus, during a disconnection of the connectors from a connecting element as a result of a rotation of the disconnecting means, the disconnecting means can be formed to be substantially circular, whereas during a disconnection of the connectors from a connecting element as a result of a translational movement of the disconnecting element, the disconnecting means can be formed to be substantially polygonal, in particular square. As a result, depending on the type of movement of the disconnecting element, in particular the process of disconnecting the connecting element from the connectors is facilitated. Rhombus, trapezoidal, elliptical or other geometric shapes are also possible for the disconnecting element.
By means of a translational or rotational movement of the disconnecting element and the preferably loss-preventing arrangement of the connecting element on the disconnecting means, a substantially simultaneous disconnection of the connecting element from both connectors and thus a reduction in the probability of electric arcs being formed during the disconnection of a current-carrying line can be achieved.
To ensure a simple and simultaneously safe initiation of a disconnecting process, it is proposed that the disconnecting device can be in the form of a pyrotechnic disconnecting device. In this case, the disconnection can be initiated preferably by igniting an ignition squib in an ignition channel. In one embodiment, the ignition channel can be arranged with a disconnecting means on for example a connection lug which is rigidly connected to the disconnecting means at the same time and holds said means in a fixed position.
As a result of the pulse caused by the ignition of the ignition squib, the connection between the ignition channel and the connection lug can be disconnected. As a result of the disconnection, the disconnecting means can no longer be held in the position thereof, whereupon said means rotates about its own axis together with the connecting element and disconnects the connecting element from the first and second connectors at a first and second contact point.
In one embodiment of a disconnecting device having a disconnecting element, the ignition channel can likewise also be arranged on a piston which, as a result of the pulse caused by the ignition of the ignition squib, is accelerated away from the ignition channel in such a way that the disconnecting means undergoes a translational movement at an angle, preferably perpendicularly to the connection plane of the connectors and of the connecting element, which movement leads to a disconnection of the connection between the ignition channel and the connection lug.
Alternatively to the disconnection by a pyrotechnic disconnecting means, the disconnection of the connectors from the connecting element can likewise take place by means of a compressed-air disconnecting means, a motor-controlled disconnecting means, a hydraulically controlled disconnecting means or a magnetically controlled disconnecting means.
Additionally, as an alternative to a disconnection by a movement of the disconnecting means, a disconnection can also take place by means of the acceleration of two disconnecting bits which are accelerated substantially at the same time towards the contact points between the connectors and the connecting element and disconnect the connectors from the connecting element at said points.
In order to ensure greater flexibility with regard to the displacement path of the disconnecting means of the disconnecting device which is the subject matter, it is proposed that the disconnecting device is formed in such a way that, in a final state of the disconnecting device, the disconnecting means is arranged in such a way that the breakdown voltage between the first and the second connector is the same as or less than between the first connector and the first contact point of the connecting element and/or between the second connector and the second contact point of the connecting element.
In the case of a round, preferably circular disconnecting means, this can be achieved for example in that the disconnecting means of the disconnecting device is rotated out of the original position by an angle of 45° or more during the disconnection. Alternatively, in the case of an angular-shaped disconnecting means, this can be achieved in that the route of a translational movement carried out during the disconnection is greater than or the same as the distance between the two connectors in the open state of the disconnecting device.
In order to prevent the formation of an electric arc as efficiently as possible, it is proposed that the disconnecting means can comprise at least one isolation element which is spatially arranged between the first and the second connector when the disconnecting device is in an open state. In this case, the isolation element can be connected to the disconnecting means in an interlocking manner, preferably with a force fit, particularly preferably in an integrally bonded manner.
In one embodiment of the disconnecting device having a round, preferably circular disconnecting means, the isolation element can preferably be formed to be partly circular—and in a closed state of the disconnecting device can be arranged directly on the connecting element. In particular in the case of such an embodiment, the disconnecting means can comprise at least two isolation elements which are spatially arranged between a first and a second connector in a closed state of the disconnecting device. This ensures that an electric arc is extinguished as quickly as possible at both disconnecting points after a disconnection of the connecting element from the connectors.
In one embodiment of the disconnecting device having an angular disconnecting means, preferably only one isolation element, which is advantageously formed to be rectangular, can be arranged directly on the connecting element in a closed state of the disconnecting device.
A particularly simple manner of arranging an isolation element at or on a disconnecting means can be achieved in that the disconnecting means is preferably formed completely from an isolation material. In this case, the disconnecting means can have only one groove or recess for receiving the connecting element and otherwise can be formed completely from an isolation material.
In order to ensure that an electric arc is extinguished sufficiently quickly and safely after the disconnection of a current-carrying line, it is proposed that the isolation element can be formed from a breakdown-resistant isolation element having a low electric conductivity, preferably a plastics material, a ceramic or a resin. In this case, the isolation element can preferably be formed from an isolation material having a breakdown resistance of at least more than 5 kV/mm, preferably more than 20 kV/mm, particularly preferably more than 50 kV/mm and/or a specific electric conductivity of at least less than 10−5 S·cm−1, preferably less than 10−10 S·cm−1, particularly preferably less than 10−15 S·cm−1.
According to one embodiment, it is proposed that the disconnecting device can comprise at least one resistor element which, immediately after the disconnection, is arranged between the connectors, thereby electrically connecting the connectors. In this case, the resistor element can be connected to the disconnecting means in an interlocking manner, preferably with a force fit, particularly preferably in an integrally bonded manner.
It has been recognised that the probability of electric arcs being formed during the disconnection of current-carrying lines can be significantly reduced if the connectors initially remain interconnected in an electrically conductive manner by at least one resistor element immediately after the disconnection, and the current is thereby initially reduced, to ultimately actually be completely disconnected. The current flow between the connectors is firstly merely limited before at least one isolation element which is spatially arranged between the first and the second connector substantially completely prevents the current flow for the purpose of complete disconnection. This arrangement corresponds to two-stage switching and reduces the risk of an electric arc being formed in that, in addition to a reduced induction voltage, the change in current over time (di/dt) in each case is reduced.
In order to reduce a current flow between the connectors as efficiently as possible, it is proposed that the resistor element can be formed from a material having a low specific electric conductivity of at least less than 102 S·cm−1, preferably less than 10−1 S·cm−1, particularly preferably less than 10−4 S·cm−1.
In one embodiment of the disconnecting device having a round, preferably circular disconnecting means, the resistor element can preferably be formed to be partly circular—and in a closed state of the disconnecting device can be arranged directly on the connecting element. In particular in the case of such an embodiment, the disconnecting means can comprise at least two resistor elements which are spatially arranged between a first and a second connector in a closed state of the disconnecting device. This ensures that the current flow is reduced as quickly as possible at the disconnecting points after a disconnection of the connecting element from the connectors.
In one embodiment of the disconnecting device comprising an angular disconnecting means, also only one resistor element, which is advantageously formed to be rectangular, can be arranged, and can be arranged directly on the connecting element in a closed state of the disconnecting device.
According to one embodiment, it is proposed that the disconnecting device can comprise at least two resistor elements which can preferably be formed from different materials having a different specific electric conductivity.
Preferably, in this case, immediately after a disconnection, the resistor elements can be arranged between the connectors in such a way that a change in current over time (di/dt) as a result of the disconnection of a current-carrying line is as small as possible.
In the case of an embodiment of the disconnecting device having a circular disconnecting means, this can be achieved for example in that two resistor elements which are formed to be partly circular and differ in terms of the specific electric conductivity thereof are arranged on the disconnecting means in such a way that, after the disconnection of an electrical connection between the connectors and the connecting element as a result of a rotation of the disconnecting means, an electrical connection is produced between the connectors by means of the two resistor elements, wherein the two resistor elements form a resistance gradient along the direction of movement of the disconnecting means so that as the angle of rotation increases, the electrical resistance between the connectors increases.
In the case of an embodiment of the disconnecting device having a rectangular disconnecting means, two resistor elements having a different specific electric conductivity can preferably be arranged in such a way that the resistor element having the higher specific electric conductivity is firstly arranged between the first and second connectors after a disconnection of the disconnecting device, before the resistor element having the lower specific electric conductivity is then arranged between the connectors. Also as a result, a resistance gradient is achieved in the direction of movement of the disconnecting means.
According to one embodiment, it is proposed that more than two resistor elements, which differ in terms of the specific electric conductivity thereof, are arranged on or at the disconnecting means, preferably in the form of a coating having a resistance material which forms a resistance gradient. This allows a disconnection of a current-carrying line having a resistance increasing in the direction of movement and thereby considerably reduces the current gradient and thus the probability of an electric arc being formed during the disconnection of a current-carrying line.
According to another embodiment, it is proposed that the disconnecting device comprises at least two disconnecting means electrically connected in series, the disconnecting means, which are spatially separated from one another, preferably being interconnected by connecting means.
The principle of minimising the probability of an electric arc being formed during the disconnection of a current-carrying line can be further optimised in that, by increasing the number of disconnecting points—provided that the disconnecting points are opened at substantially the same time—the voltage induced by the change in current is divided between a plurality of disconnecting points.
According to another embodiment, it is proposed that, in a parallel arrangement, a first and second connector, in the closed state of the disconnecting device, are electrically interconnected by means of two connecting elements at a first and second contact point and a third and fourth contact point—and as a result of a rotational or translational movement of the disconnecting means, can be disconnected from one another at substantially the same time.
As a result, the principle of minimising the probability of an electric arc being formed during the disconnection of a current-carrying line can be further optimised, since by means of the parallel arrangement of two connecting elements, and two disconnecting points arranged in parallel being opened at substantially the same time, not only the induced voltage, but also the current flow in each of the disconnecting points is halved in comparison with only one disconnecting point.
It is understood that all the embodiments and examples of a series arrangement of a disconnecting device are equally transferable to a parallel arrangement of a disconnecting device. Accordingly, the probability of an electric arc being formed during the disconnection of a current-carrying line can also be further reduced in the parallel embodiment by the additional integration of resistor elements in the form of a resistance gradient.
In order to ensure electrical isolation, it is proposed that the disconnecting device can be arranged in a housing. It can thus be achieved that, during a disconnection of a current-carrying line, despite the formation of an electric arc, no flashover to the environment takes place.
In this case, the housing can preferably be formed from a breakdown-resistant material having a low specific electric conductivity, in particular a plastics material, a ceramic or a resin.
A further subject matter is a method for disconnecting a power line, in which at least one disconnecting signal is received, before at least one signal, in particular a control signal for igniting an ignition squib is triggered in such a way that the electrical connection between a connecting element arranged on a disconnecting means and a first connector at a first contact point and between the connecting element and a second connector at a second contact point is disconnected in such a way that a breakdown voltage between the first and the second connector in the disconnected state of the disconnecting device is greater than between the first connector and the first contact point of the connecting element and/or between the second connector and the second contact point of the connecting element.
The method for disconnecting a power line can preferably be designed in such a way that a disconnection of the disconnecting means takes place at at least two contact points at substantially the same time.
In order to protect the vehicle occupants of a motor vehicle from a short circuit of a current-carrying line in a reliable and simultaneously simple manner in the event of an accident, the method for disconnecting a power line, in particular the disconnecting signal, can preferably be coupled to the triggering of an air-bag control signal.
Alternatively or in addition to the coupling of the method of the subject matter to an air-bag control signal, the method can also be coupled to the behaviour of other vehicle components, such as to the behaviour of the seatbelt pre-tensioner, the seatbelt force limiter or the roll-over bar.
In particular, the method of the subject matter can also be coupled to signals of crash or impact sensors.
According to one embodiment, it is proposed that the disconnecting signal is received from a sensor, preferably a reed sensor, a Hall sensor or an induction sensor.
To be able to transmit the disconnecting signal safely and without interference, the disconnecting signal can be transmitted preferably galvanically from the electric circuit. This can be achieved in particular in that the sensor is arranged in an electrically isolated manner for example on a housing of the disconnecting device.
According to another embodiment, a method for disconnecting a power line is proposed in which, in addition to the disconnection of an electrical connection, in particular at substantially the same time as the disconnection of an electrical connection, an electrical connection is produced which makes it possible to discharge stored electrical energy, in particular to discharge an intermediate circuit voltage from an intermediate circuit capacitor.
It has been recognised that, in particular when disconnecting current-carrying lines of the high-voltage power supplies of electric or hybrid vehicles which comprise intermediate electric circuits having intermediate circuit capacitors, it must be ensured that these electric circuits are also discharged during a disconnection of the current-carrying lines to prevent people from being at risk as a result of high voltage.
The subject matter is explained in more detail below with reference to a drawing showing embodiments, in which:
Wherever possible, the same reference signs have been used for like elements in the drawings.
The connecting element 8 and the connectors 2, 4 can be formed preferably from an electrically conductive material, such as a copper material or an aluminium material. In this case, the connectors 2, 4 and the connecting element 8 can also be formed from different materials.
The connecting element 8 can preferably be in the form of a flat cable. It is understood that, according to another variant, round cables can equally be used instead of flat cables. At the same time, a combination of round and flat cables can also be provided. The connecting element 8 can preferably be arranged on the disconnecting means 6. The connecting element 8 is preferably a metal conducting path which is preferably arranged in a groove or recess in the disconnecting means 6.
As shown in
The contact points 10a, 10b can advantageously be in the form of predetermined breaking points comprising taperings of material. For this purpose, in the closed state of the disconnecting device 1, for example the material cross sections in the corresponding contact regions 10a, 10b between the connectors 2, 4 and the connecting element can be smaller than at the connectors 2, 4 and/or the connecting element 8. Preferably, the contact regions 10a, 10b can also be formed from a material which firstly has a low material strength, and secondly has a high current load capacity.
The connection lug 12′ attached to the ignition channel 12 can also comprise a predetermined breaking point which can preferably be arranged at the contact point between the connection lug 12′ and ignition channel 12.
By means of the embodiment shown in
By means of the embodiment shown in
As shown in
The main direction of movement of the pin 16′ can be seen from
In this case,
The resistor elements can preferably be formed from a material having a low specific electric conductivity of less than 102 S·cm−1, preferably less than 10−1 S·cm−1, particularly preferably less than 10−4 S·cm−1. The resistor elements can be connected to the disconnecting means 6, in particular soldered, bonded or welded. Likewise, the resistor elements can also be connected to the disconnecting means 6 in an interlocking manner, in particular as a tongue-and-groove or dovetail connection. More than only two resistor elements can also be arranged on the disconnecting means 6, which elements can preferably be formed from different materials having different specific electric conductivity in each case.
As already mentioned, more than only two resistor elements 18a, b can also be arranged on the disconnecting means 6 which can preferably be formed from different materials having different specific electric conductivities in each case. It has been recognised that the formation of an electric arc during the disconnection of a current-carrying line can be prevented as efficiently as possible in that resistor elements are arranged on the disconnecting means 6 forming a resistance gradient in the direction of movement. By means of this type of the arrangement, instead of an abrupt disconnection of a power line, a more gentle disconnection of a power line can be achieved in which there is a lower current gradient, which counteracts the formation of electric arcs.
In this case, the two partly circular regions from
By means of the embodiment shown in
It is understood that in the embodiment according to
The connecting elements 8a, b can preferably be in the form of flat conductors. However, it is understood that the connecting elements 8a, b can also be in the form of round conductors. Preferably, the connecting elements 8a, b can be oriented substantially parallel to one another and have substantially the same length and the same cross section. In addition, the two connecting elements 8a, b can advantageously be formed from the same material.
With the embodiment shown in
By means of the combination shown in
Furthermore,
In addition, to disconnect the connecting elements from the first and second connectors in the first electric circuit, the third connecting element 8c is shifted by the movement in such a way that it produces an electrical connection between the second connector and the second electric circuit at substantially the same time. Thus, according to the final state—as can be seen from
By means of the embodiment shown in
It is understood that a disconnecting device for a power line 1 for simultaneously disconnecting and producing an electrical connection can likewise be formed by means of a combination of a second electric current with any other embodiment of one of the disconnecting devices presented here, provided that, in an initial state, one of the two electric circuits is closed, whereas the other electric circuit is open, and in a subsequent final state, the previously open electric circuit is closed, whereas the previously closed electric circuit is now in an open state.
Number | Date | Country | Kind |
---|---|---|---|
10 2016 113 156.3 | Jul 2016 | DE | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2017/059105 | 4/18/2017 | WO | 00 |