DE102015007420A1 - Device and method for interrupting or establishing an electrical connection - Google Patents

Abstract

The invention relates to a device for interrupting or producing an electrical connection, comprising a conductor (2) forming the electrical connection and a material (5) which can be inflated by heat supply in the vicinity of the conductor (2), wherein at least a portion of the conductor ( 2) is movable and / or deformable by an irreversible swelling of the inflatable material (5) such that the electrical connection is interrupted or produced.

Description

The invention relates to a device and a method for interrupting or establishing an electrical connection.

In the prior art devices are known in which an electrical connection formed by a conductor is interrupted by igniting a pyrotechnic mixture. By igniting the pyrotechnic mixture, a sufficiently strong gas pressure is generated or sufficient amount of thermal energy is released, so that the conductor is destroyed. However, this can also trigger a fire. It also comes to a bang.

The object of the invention is to eliminate the disadvantages of the prior art. In particular, a device and a method for interrupting or establishing an electrical connection are to be specified in which the risk of fire is significantly reduced and the formation of a strong bang is avoided.

This object is solved by the features of claims 1 and 8. Advantageous embodiments of the invention will become apparent from the features of claims 2 to 7 and 9 to 13.

According to the invention, the device comprises a conductor forming the electrical connection and a material which can be inflated by supplying heat in the vicinity of the conductor, wherein at least a portion of the conductor is movable and / or deformable by an irreversible swelling of the inflatable material such that the electrical Connection is interrupted or established.

An inflatable material is understood to mean a material whose volume can be increased. The puffing, d. H. the increase in volume, can be introduced by heat. The inflation takes place when an activation temperature is reached. The activation temperature is advantageously in the range of about 100 ° C to about 200 ° C. Preferably, the activation temperature is between 140 ° C and 160 ° C.

The puffing is further referred to as irreversible, because the inflatable material remains inflated after inflation even at a completion of the heat supply or cooling. However, it may come to a slight reduction in volume after the completion of the heat supply or cooling.

Preferably, the volume of the inflatable material may increase at least tenfold. Particularly preferred is an inflatable material whose volume can be at least hundreds of times. For the purposes of the invention, the puffing of an explosion, the z. B. when igniting a pyrotechnic mixture is to delineate. The inflatable material increases the volume that occupies the material as a solid. This is to be distinguished from an explosive material, which can suddenly release a larger amount of energy, especially in the form of thermal energy and can thereby generate a high gas pressure.

The device according to the invention can occur in two alternative embodiments. It is either designed so that an originally existing electrical connection can be interrupted by the inflating of the inflatable material, or it is designed so that an originally non-existent electrical connection can be made by the inflation of the inflatable material.

In the device according to the invention, the force for interrupting or establishing the electrical connection is applied by the inflatable material. Neither a high gas pressure is generated, nor a larger amount of thermal energy released. Thus, the emergence of a strong bang can be prevented and the risk of fire can be significantly reduced. Since the puffing is irreversible, the electrical connection is permanently interrupted or produced even if the heat supply is terminated or cooled.

According to an advantageous embodiment of the invention, the inflatable material comprises expanded graphite. Expanded graphite has a layer structure such as graphite, wherein between individual layers foreign molecules are incorporated. Expanded graphite is characterized by a particularly large volume increase during inflation. The increase in volume of expandable graphite can be adjusted to a factor between 8 and 400 during production. Preferably, the factor is between 20 and 150.

According to a further advantageous embodiment of the invention, the conductor is integrally formed. The one-piece conductor can be interrupted by the inflating of the inflatable material.

According to a further advantageous embodiment of the invention, the conductor for forming the electrical connection form, force and / or materially connected to another conductor. Here, the two alternatives come into consideration: either an existing positive, non-positive and / or material connection of the conductor with another conductor can be broken by the inflating of the inflatable material and thereby the electrical connection can be interrupted. Or it initially there is no connection of the conductor with the other conductor. By inflating the inflatable material, a positive, non-positive and / or material connection of the conductor with the other conductor can be generated and thereby the electrical connection can be established.

According to a further advantageous embodiment of the invention, the device comprises an electrical and / or a pyrotechnic heating element, with which heat can be supplied to the inflatable material. Advantageously, there is good heat conduction between the heating element and the inflatable material. The heat generated by the heating element is substantially completely supplied to the inflatable material. For this purpose, the heating element can rest directly on the inflatable material. The inflatable material may for example be glued to the heating element with a thermal paste. The heating element may additionally be thermally stripped on its sides facing away from the inflatable material. The pyrotechnic mixture used in a pyrotechnic heating element can be made much weaker than a pyrotechnic mixture conventionally used to break conductors. As a result, the emergence of a strong bang can be prevented and the risk of fire can be significantly reduced.

According to a further advantageous embodiment of the invention, the device further comprises a cutting device, wherein the device is configured so that the cutting device is displaced due to a swelling of the inflatable material such that it cuts through the conductor and thereby breaks the electrical connection. The cutting device is advantageously formed of a non-conductive material. The cutting device allows concentration of the force of the inflating inflatable material on a particular area of the conductor. The leader can thus be purposefully interrupted in the specific area.

According to a further advantageous embodiment of the invention, the device further comprises a pole for connection to a pole of a starter battery. The device can thus be used as a pole connector z. B. be used in a car and provide an electrical connection between a consumer, in particular a high-current consumer, and the starter battery. In an accident, the inflatable material can be inflated by heat. The inflatable inflatable material interrupts the electrical connection between the load and the starter battery. By interrupting the electrical connection occurring short circuits and fires can be avoided as a result of an accident.

A device according to the invention can, for. B. be used in an electric car. In an electric car, several batteries are usually combined to form battery modules. Failure of one or more batteries results in the need to interrupt the electrical connection to the failed batteries. In order to be able to continue to operate the electric car with the functional batteries, it is necessary to be able to establish an electrical connection between the still functioning batteries while bridging the failed batteries. For connecting successive batteries, devices according to the invention may each be provided in the embodiment in that they initially each provide an electrical connection between the batteries. A failed battery can then be electrically disconnected from it by inflating the inflatable material into the devices of the invention connecting them to the adjacent batteries. Further devices according to the invention can provide bypasses between batteries which are not in immediate succession. The bypasses initially do not form an electrical connection. By inflating the inflatable material, a bypass can establish an electrical connection between two non-consecutive batteries to bypass one or more failed and disconnected batteries.

According to the invention, the method comprises the following steps:
Providing a conductor forming the electrical connection and a material which can be inflated by supplying heat in the vicinity of the conductor,
Applying heat to the inflatable material, so that the inflatable material inflates irreversibly and at least a portion of the conductor is so moved and / or deformed by the inflation that the electrical connection is interrupted or produced.

When supplying the heat, the amount of heat is to be dimensioned so that the inflatable material is heated at least to the activation temperature. The activation temperature is advantageously in the range of about 100 ° C to about 200 ° C, preferably between 140 ° C and 160 ° C. Advantageously, the expanded graphite reaches the activation temperature within less than 10 seconds after the start of the heat supply, preferably within less than one second after the start of the heat supply. Advantageously, the electrical connection is made by the inflating of the inflatable material within less than 10 s after the Reaching the activation temperature interrupted or established, preferably within less than a second after reaching the activation temperature.

According to a further advantageous embodiment of the invention, the supply of heat by actuating a switch and / or by opening or closing a connector is triggered.

According to a further advantageous embodiment of the invention, the electrical connection is interrupted or produced by a positive, non-positive and / or cohesive connection is separated or generated. There are two alternatives: either an existing positive, non-positive and / or material connection can be broken by the inflating of the inflatable material and thereby the electrical connection can be interrupted. Or at first there is no electrical connection. By inflating the inflatable material can be a positive, cohesive and / or cohesive connection generated and thereby the electrical connection can be made.

According to a further advantageous embodiment of the invention, the supply of heat by an electric and / or a pyrotechnic heating element takes place.

According to a further advantageous embodiment of the invention, the heat is supplied by an exothermic solid-state reaction to produce solids, gases and / or vapors. The reacting solids are advantageously directly on the inflatable material, so that the heat generated during the solid-state reaction is supplied as completely as possible to the inflatable material. The generated solids, gases and / or vapors can assist the inflation of the inflatable material.

According to a further advantageous embodiment of the invention, the feeding of the heat takes place through an electric current passing through the inflatable material. A prerequisite for this is that the inflatable material is conductive at least in a certain direction. Expanded graphite, like graphite, has a layer structure which has an almost metallic conductivity along the layers but is hardly conductive perpendicular to the layers. Thus, contacts can be attached to the expandable graphite in such a way that a flow of current can be generated along the layers. As soon as the expandable graphite is heated to the activation temperature by the current flow, the expandable graphite swells. During swelling, the layer structure of the expanded graphite is destroyed. Accordingly, the expandable graphite loses its conductivity.

An exemplary embodiment of the invention will be explained in more detail below with reference to the single FIGURE.

The single figure shows schematically the pole connector 1 designed inventive device. The pole connector 1 includes a ladder 2 , a conductive connection part 3 , a heating element 4 and a piece of expanded graphite 5 ,

The connecting part 3 has a first 6a and a second conical recess 7a on. The first conical recess 6a opens into a receiving space in which the heating element 4 and the piece of expanded graphite 5 are included. Preferably, the heating element 4 and the piece of expanded graphite 5 each pressed into the receiving space. The leader 2 has a conical end 6b which is in the first conical recess 6a is pressed. The connecting part 3 is with the second conical recess 7a on a preferably also conically shaped pole 7b a starter battery 8th appropriate. The pole 7b is in the second conical recess 7a added. As a result, there is an electrical contact between the pole 7b and the connecting part 3 ,

Advantageously, the conductor 2 and the connecting part 3 In addition, an insulating protective layer on its surface. The insulating protective layer is at the conical end 6b or at the first 6a and second conical recess 7a not provided.

The function of the pole connector 1 is the following:
The pole connector 1 forms an electrical connection between a consumer and the starter battery 8th , This is the head 2 over the connecting part 3 with the pole 7b conductively connected. In an accident, the heating element 4 for example, activated by the accident detecting sensors, so that it is the piece of expanded graphite 5 Adds heat. Once the temperature of the expanded graphite 5 an activation temperature of z. B. has reached 150 ° C, it comes to an irreversible puffing of expanded graphite 5 , Due to the arrangement of the piece of expanded graphite 5 the inflation initially occurs only in the opening direction of the first conical recess 6a , The expanding expanded graphite presses 5 the conical end 6b of the leader 2 from the first conical recess 6a out. This will cause the electrical contact between the conductor 2 and the connecting part 3 interrupted. As a result, also the electrical connection between the consumer and the starter battery 8th interrupted. Preferably, the expandable graphite swells 5 from the first conical recess 6a out and presses the ladder 2 completely out of the first conical recess 6a , Moving the conductor 2 can be limited by a holding device (not shown). Because the swelling of expandable graphite 5 is largely irreversible, the electrical connection between the consumer and the starter battery remains 8th permanently interrupted. Inflated expanded graphite 5 is hardly electrically conductive. In addition, however, the piece of expanded graphite 5 be wrapped in an insulating material. The insulating material is preferably designed so elastic that it also after the inflation of the expandable graphite 5 this wrapped and thereby electrically isolated.

LIST OF REFERENCE NUMBERS

1

pole connector

2

ladder

3

connecting part

4

heating element

5

expandable graphite

6a

first conical recess

6b

conical end

7a

second conical recess

7b

pole

8th

starter battery

Claims (13)

Device for breaking or establishing an electrical connection, comprising a conductor forming the electrical connection ( 2 ) and one near the conductor ( 2 ) arranged by heat supply inflatable material ( 5 ), wherein at least a portion of the conductor ( 2 ) by an irreversible swelling of the inflatable material ( 5 ) is movable and / or deformable such that the electrical connection is interrupted or produced. Apparatus according to claim 1, wherein the inflatable material ( 5 ) Comprises expandable graphite. Device according to claim 1 or 2, wherein the conductor ( 2 ) is integrally formed. Device according to claim 1 or 2, wherein the conductor ( 2 ) To form the electrical connection form, force and / or materially connected to another conductor. Device according to one of the preceding claims, wherein the device comprises an electric and / or a pyrotechnic heating element ( 4 ), with which heat to the inflatable material ( 5 ) can be fed. Device according to one of the preceding claims, further comprising a cutting device, wherein the device is designed such that the cutting device due to a swelling of the inflatable material ( 5 ) is moved in such a way that it 2 ) and thereby breaks the electrical connection. Device according to one of the preceding claims, further comprising a pole receptacle for connection to a pole ( 7b ) of a starter battery. A method of breaking or establishing an electrical connection, comprising the steps of: providing a conductor forming the electrical connection ( 2 ) and one near the conductor ( 2 ), inflatable by heat supply material ( 5 ), Supplying heat to the inflatable material so that the inflatable material ( 5 ) inflates irreversibly and at least a portion of the leader ( 2 ) is so moved and / or deformed by the inflation that the electrical connection is interrupted or established. A method according to claim 8, wherein the supply of the heat is triggered by operating a switch and / or by opening or closing a connector. The method of claim 8 or 9, wherein the electrical connection is interrupted or produced by a positive, non-positive and / or material connection is separated or generated. Method according to one of claims 8 to 10, wherein the supply of heat by an electric and / or a pyrotechnic heating element ( 4 ) he follows. A method according to any one of claims 8 to 11, wherein the heat is supplied by an exothermic solid-state reaction to produce solids, gases and / or vapors. Method according to one of claims 8 to 12, wherein the supply of heat by a the inflatable material ( 5 ) continuous electric current takes place.

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