LOW-, MEDIUM-, AND / OR HIGH-VOLTAGE SYSTEM WITH A LONG-TERM STABLE AND MATERIALLY INTEGRATED CURRENT PATH CONNECTION USING NANOMATERIALS AND METHOD FOR PRODUCING THIS CURRENT PATH CONNECTION

Description

[0001] The invention relates to a method for producing a material-to-material current path connection in medium- and / or high-voltage switching devices and to a medium- or high-voltage switching device with a long-term stable and material-to-material current path connection.

[0002] In medium-voltage and high-voltage systems, the current is carried via cables, in what is known as the current path. The same applies to medium-voltage and high-voltage switchgear, which are also referred to below as medium-voltage and high-voltage systems.

[0003] When conducting the rated current in a conductor, heat is generated due to the ohmic resistance of the switchgear's current path. To ensure the long-term functionality of the switchgear, it must be ensured that the components installed in the device, especially the conductors that form the current paths, can withstand this heating over the long term. Since "long-term" in connection with switchgear generally refers to the entire service life of the switchgear, special requirements must be placed on the switchgear's current paths.

[0004] In this context, force-locking connections in the current path must be viewed with particular scrutiny. Such force-locking connections, typically screw connections or clamping points, run the risk of their resistance increasing significantly over the course of their service life, for example, due to corrosion. An increase in resistance in the current path inevitably leads to higher temperatures in the affected areas. This carries the risk of critical temperatures being reached and / or exceeded, rendering the switchgear no longer suitable for carrying the intended rated current under the potential or specified environmental conditions.

[0005] This is particularly critical because force-locked connections usually have a higher electrical resistance than other types of connections and thus intensify the heating problem or cause it to occur in the first place.

[0006] The problem of increasing resistance in force-locked connections over the course of a switchgear's service life is avoided in the state of the art by using material-locked connections, welded connections or soldered connections.

[0007] DE 10 2009 002135 A1 discloses a method for contacting printed circuit boards with a nano-sintering paste.

[0008] US20100018768A1 discloses a crimp connection in connection with a metallic connection.

[0009] WO2010108726 A1 discloses a connection using a nanofoil.

[0010] US4334122 describes a manufacturing method for an electrical termination made of two metals, wherein the two metals are bonded together by means of pressure and heat.

[0011] However, the creation of welded or soldered joints is generally associated with an increase in the temperature of the components being joined. For sensitive components, such as vacuum interrupters or other temperature-sensitive components, and especially the plastic components they contain, a cost-effective, simple welding or soldering method is critical because there is a risk that the process heat generated during joining could damage or destroy these components, thus compromising their functionality.

[0012] In the state of the art, very expensive welding processes such as electron beam welding or laser welding are generally used for such components, which only lead to locally limited heating, especially in the immediate vicinity of the connection point, of the components to be joined.

[0013] The object of the invention is to provide a long-term stable and conductive connection to the power line in a switchgear, which eliminates the disadvantages of the prior art or provides a cost-effective and less complex production of connections of electrical current paths.

[0014] This problem is solved by independent claim 1 and the claims dependent on this claim.

[0015] One embodiment relates to a method according to claim 1.

[0016] The force-locking connection exerts pressure on the connection point, which has a positive effect on the formation of the connection between the first part of the current path and the second part of the current path. By applying reaction energy, a conductive and cohesive connection is formed between the first part and the second part of the current path with the cooperation of the nanomaterial. The nanomaterial can subsequently be present as such or as a precursor of the nanomaterial; i.e., the actual nanomaterial is formed from a precursor through a reaction, preferably by applying reaction energy, which also leads to the formation of the cohesive connection.

[0017] A nanomaterial is a material whose individual units or one or more dimensions are between 1 and 1000 nanometers (10 -9< meters, billionths of a meter), preferably between 1 and 100 nanometers.

[0018] For the purposes of this application, the term "region" refers to the connection region, i.e. the region in which the first part and the second part of the current path are connected to each other by means of the nanomaterial.

[0019] The term "conductive" in the context of this application means that the conductive, interconnected parts of a current path are conductive across the connection in such a way that, when loaded at or below the rated current of the switchgear, there is no impairment of function, nor does it result in heating of the connection point that exceeds the permissible temperatures.

[0020] By using the nanomaterial and converting the purely force-locking connection into a material-locking and / or force-locking connection by supplying reaction energy, a long-term stable connection is ensured, which is classified as a material-locking connection according to the standards and therefore does not require any additional testing effort, such as force-locking or form-locking connections.

[0021] In particular, a force-locking connection and / or a form-locking connection, in which pressure is exerted on the connection point between the first part of the current path and the second part of the current path, has a positive effect on the formation of the material connection between the first part of the current path and the second part of the current path.

[0022] It is preferred that the nanomaterial is located between the respective non-positively and positively connected regions of the first part and the second part of the current path or that the nanomaterial extends beyond the respective regions of the first and / or the second current path.

[0023] The complete or almost complete presence of nanomaterial in the connection area of ​​the current path achieves a low electrical resistance of the connection area and / or aging resistance. The connection area here also refers to the area in which the first and second parts of the current path are connected by means of the nanomaterial and the frictional and / or positive locking.

[0024] It is further preferred that the first part and the second part of the current path be formed from the same conductive material and / or the same material combination. Alternatively, the first part and the second part of the current path can be formed from different conductive materials and / or different material combinations; in particular, copper and silver or copper alloys and silver alloys are relevant for different pairings.

[0025] It is also preferred that the nanomaterial and / or a precursor of the nanomaterial be applied in the form of a paste, a film, and / or a powder to the respective region of the first and / or second part of the current path and / or be present in the respective region of the first and / or second part of the current path. Thus, both parts or only a part of the current path to be connected can contain the nanomaterial.

[0026] It is particularly preferred that a film be formed from the nanomaterial, in particular by printing, especially by screen printing, or by doctoring or spreading onto a transfer material from which the film produced by, for example, drying, curing, or pressing can be removed. Alternatively, the transfer material can also be converted, incorporated into the bond, or degraded during the formation of the cohesive bond.

[0027] It is particularly preferred that the connecting means are formed by one or more means of screws, rivets and / or clamps.

[0028] It is also preferred that the first part and the second part of the current path are positively connected to one another.

[0029] It is also preferred that the first part of the current path is an electrically conductive and flexible current strip or a pole head or a current strip terminal, and / or the second part of the current path is a connection to: a moving contact or fixed contact of a vacuum interrupter; or a transformer; or a busbar.

[0030] It is also preferred that the supply of the reaction energy to a reaction locally limited to the first part adjacent to the nanomaterial and the second part of the current path adjacent to the nanomaterial leads to a material connection between the first part and the second part of the current path.

[0031] It is further preferred that the reaction energy be supplied to the nanomaterial in the form of thermal energy and / or electrical energy, and / or that the reaction energy be supplied in another form and converted into thermal energy and / or electrical energy in and / or on the nanomaterial. However, it is also possible to supply the reaction energy to the material in the form of electromagnetic oscillations, waves, and / or induced oscillations and / or shock waves.

[0032] It is also preferred that the material connection of the first part, the second part of the current path and the nanomaterial brought about by the supply of the reaction energy is based on a sintering process of the nanomaterial or comprises a sintering process of the nanomaterial and / or is based on welding and / or soldering of the first part and the second part of the current path by an exothermic reaction of the nanomaterial or a part of the nanomaterial. During the sintering process, the nanomaterial bonds to one another and at least partially or completely to the first and second parts of the current path. During the exothermic reaction, the first and second parts of the current path can be welded directly to one another and / or welded with the involvement of the nanomaterial or components thereof and / or the first and second parts of the current path can be soldered with the cooperation of the nanomaterial or other materials.The other materials can in particular also be components of the nanomaterial or have been formed during the exothermic reaction.

[0033] It is also preferred that the nanomaterial comprises silver and / or a silver precursor.

[0034] Preference is also given to nanomaterial which comprises silver nanoparticles in agglomerates with dimensions in at least one spatial direction of more than 90 nm, in particular more than 100 nm or 200 nm, and less than 300 nm. In particular, it is also preferred that the silver nanoparticles are formed at a corresponding reaction temperature and / or corresponding reaction conditions and have a size of 1 nm to 20 nm in at least one spatial direction.

[0035] It is further preferred that the silver nanoparticles are formed at least partially by a reaction in a metal-organic precursor.

[0036] A further embodiment is a medium or high voltage switching device according to claim 10.

[0037] The subject matter of the invention is explained in more detail below with reference to three figures: Figure 1: Material-locking and force-locking connection of a first and a second part of a current path; Figure 2: Schematic representation of a connection of a vacuum interrupter to a conductive and flexible current strip using nanomaterials; and Figure 3: Flowchart of a method according to the invention for producing a material-locking and force-locking current path connection.

[0038] The Figure 1 shows a connection in a switchgear assembly 1 not shown in detail, wherein a first part of a current path 10 is non-positively connected to a second part of a current path 20 by means of a connecting means 40 and is materially connected via a nanomaterial 30.

[0039] The force-locking connection 40 can be achieved, for example, by screws, rivets, and / or clamps. As an alternative to the force-locking connection with a connecting means 40, a form-locking connection—not shown here—can also be used. The form-locking connection can be achieved, for example, by connecting areas of the first and second parts of the current path that engage one another or by forming, for example, pressing or crimping.

[0040] The Figure 2shows the connection of a vacuum interrupter 2 in a switchgear 1 (not shown in detail), wherein the moving contact terminal 25 and the flexible current strip 15 are, on the one hand, non-positively connected to one another via a connecting means 40 and, on the other hand, are integrally connected to one another via a nanomaterial 30. Alternatively—not shown here—the moving contact bolt 25' and the flexible current strip 15 can also be, on the one hand, non-positively connected to one another via a connecting means 40 and, on the other hand, be integrally connected to one another via a nanomaterial 30. In this example, the flexible current strip 15 is integrally connected to another part of the current path 50, wherein this integral connection is a conventional welded or soldered connection.

[0041] The Figure 3shows a schematic sequence of the method according to the invention for producing a materially bonded and force-locking and / or positive-locking connection of a first and a second part of a current path in a switchgear 1, in particular a switchgear for medium voltages and / or high voltages. In a first step 100, the first part of a current path and / or the second part of a current path are provided with a nanomaterial at least in one region, or the parts of the current path provided with a nanomaterial are provided. This also includes providing the nanomaterial in the form of a film or grid, and placing the film or grid on the first part of a current path and / or the second part of a current path or between them.

[0042] In a second step 200, a force-locking and / or form-locking connection is brought about between the first part of the current path and the second part of the current path.

[0043] In a third step 300, a conductive and cohesive connection between the first part of the current path and the second part of the current path is established by applying reaction energy with the assistance of the nanomaterial. The nanomaterial can either form the conductive connection through a process comprising a sintering process or, by applying reaction energy, cause an exothermic reaction that welds the first part of the current path to the second part of the current path. List of reference symbols

[0044] 1Switchgear 2Vacuum interrupter 10First part of a current path 15Conductive, flexible current strip as the first part of the current path 20Second part of a current path 25Moving contact connection of a vacuum interrupter as the second part of the current path 25Moving contact pin of a vacuum interrupter as the second part of the current path 30Nanomaterial 40Connecting element, for example screw, rivet or clamp 50Further part of the current path 100Step 1 200Step 2 300Step 3

Claims

1. Method for establishing a materially bonded current path connection in medium- or high-voltage switching devices, wherein a current path has at least one first portion (10) and one second portion (20), wherein - the first portion (10) and / or the second portion (20) of the current path each contain a nanomaterial (30) at least in one region, - the first portion (10) and the second portion (20) of the current path are connected to one another in a non-positively locking and / or positively locking manner at least in the respective regions, - the first portion (10) and the second portion (20) of the current path are connected in a non-positively locking manner by one or more connecting means (40) in the respective regions, and - a conductive and materially bonded connection between the first portion (10) and the second portion (20) of the current path is formed, with involvement of the nanomaterial (30), by supplying reaction energy, wherein the current path connection with long-term stability is ensured using the nanomaterial and changing the purely non-positively locking connection into a materially bonded and non-positively locking connection by supplying the reaction energy.

2. Method according to Claim 1, characterized in that the nanomaterial (30) is located between the respective regions of the first portion (10) and of the second portion (20) of the current path which are connected to one another in a non-positively locking and positively locking manner or the nanomaterial (30) extends beyond the respective regions of the first (10) and / or of the second (20) current path.

3. Method according to Claim 1 or 2, characterized in that the first portion (10) and the second portion (20) of the current path are formed from the same conductive material and / or the same material combination.

4. Method according to one of the preceding claims, characterized in that the nanomaterial (30) is applied to the respective region of the first portion (10) and / or of the second portion (20) of the current path and / or is present on the respective region of the first portion (10) and / or of the second portion (20) of the current path in the form of a paste, a foil and / or a powder and / or a precursor.

5. Method according to Claim 1, characterized in that the connecting means (40) are formed with one or more means from amongst screws, rivets and / or clamps.

6. Method according to one of the preceding claims, characterized in that - the first portion (10) of the current path is an electrically conductive and flexible current conductor (15) or a pole head or a current conductor clamp, and / or - the second portion (20) of the current path is a connection o to a moving contact (25) or fixed contact of a vacuum interrupter, o to a transformer, or o a busbar.

7. Method according to one of the preceding claims, characterized in that supplying the reaction energy leads to a materially bonded connection between the first portion (10) and the second portion (20) of the current path, which materially bonded connection is locally limited to the first portion (10), which adjoins the nanomaterial (30), and the second portion (20), which adjoins the nanomaterial, of the current path.

8. Method according to one of the preceding claims, characterized in that the reaction energy - is supplied to the nanomaterial (30) in the form of thermal energy and / or electrical energy, and / or - the reaction energy is supplied in another form and is converted into thermal energy and / or electrical energy in and / or on the nanomaterial (30).

9. Method according to one of the preceding claims, characterized in that the materially bonded connection of the first portion (10), the second portion (20) of the current path and the nanomaterial (30), which materially bonded connection is created by supplying the reaction energy, is based on a sintering process of the nanomaterial (30) or comprises said sintering process and / or is based on welding of the first portion (10) and the second portion (20) of the current path due to an exothermic reaction of the nanomaterial (30) or of a portion of the nanomaterial (30).

10. Medium- or high-voltage switching device, wherein the medium- or high-voltage switching device has a current path with a materially bonded and non-positively locking current path connection, wherein the current path connection is formed in accordance with a method of preceding Claims 1 to 9, wherein the current path has at least one first portion (10) and one second portion (20), wherein the first portion (10) and / or the second portion (20) of the current path each contain a nanomaterial (30) at least in one region, wherein the first portion (10) and the second portion (20) of the current path are connected in a non-positively locking manner by one or more connecting means (40) in the respective regions, and wherein a conductive and materially bonded connection between the first portion (10) and the second portion (20) of the current path is formed, with involvement of the nanomaterial (30).