EP4018017A1

EP4018017A1 - Electrical connecting structure and method for producing such a structure

Info

Publication number: EP4018017A1
Application number: EP21702868.7A
Authority: EP
Inventors: Michael Nielsen
Original assignee: Interplex NAS Electronics GmbH
Current assignee: Ennovi Advanced Engineering Solutions Germany GmbH
Priority date: 2020-03-26
Filing date: 2021-01-20
Publication date: 2022-06-29
Also published as: CN114747091A; US20230133468A1; WO2021190798A1

Abstract

The invention relates to an electrical connecting structure and to a method for producing an electrical connecting structure (10) for use as a means for transmitting electrical energy between a first electrical component and a second electrical component, wherein the connecting structure (10) is formed by a number of layers (20, 30, 40, 50) arranged in series with one another, wherein a first outer layer (20) and a second outer layer (50) respectively consist of aluminium or an aluminium alloy and wherein furthermore a third layer (30) and a fourth layer (40), specifically two inner layers, are provided between the outer layers (20, 50), wherein the inner layers (30, 40) are respectively produced by cold gas spraying.

Description

Electrical interconnection structure and method of making such a structure

Description:

The invention relates to an electrical connection structure and a method for manufacturing such a structure

When connecting elements separated from one another between an electrical energy source and an electrical energy sink, various connection solutions are used in the prior art. In addition to the traditional unsolvable processes, such as soldering or welding, there are also called releasable electrical connections, such as plug connections, screw connections, clinch connectors, crimp connectors, to name but a few. In various applications, such as battery connections, busbars and power distributors, there is always a material mix of components to be connected to one another, and corrosion problems and corresponding consequential problems. In particular, the connection to aluminum as a line material is inadequately solved in the prior art.

Many attempts have been made in order to solve the connection problem between different materials, for example in the body shop, while maintaining the existing resistance spot welding systems, especially for aluminum and steel. Some well-known techniques are presented below. The patent DE 10015713 A1 discloses a method in which a solid rivet is inserted into the aluminum sheet. This should create an I-shape that clamps the aluminum sheet. Then the aluminum sheet is to be welded to another sheet steel by means of resistance spot welding via the steel rivet element. This rivet element has two flat surfaces.

There are other methods of combining metallic materials with one another. In roll cladding, for example, two or more different materials are combined with one another in order to be able to optimally use the best properties of the individual materials. Even materials that are normally not easily welded can be connected to one another by installing intermediate layers. This applies to both full-surface and strip-shaped designs. When cladding, therefore, at least two different metallic strips are combined to form a composite material. The materials typically run in parallel from respective coil into the rolling mill and, depending on the metal and material properties, are connected to one another by high rolling pressure.

For the coating, materials such as precious metals or precious metal alloys based on gold, palladium and silver, as well as copper and copper alloys, nickel, aluminum and aluminum-silicon can be used. However, the method is not suitable for use in a busbar or a power distributor, since the affected connection points have, for example, bolts and / or bores in order to connect the connection partners by means of a screw bolt and a nut. This results in further material combinations and various surface sections at the connection points are not covered by the roll cladding.

Another alternative is the galvanic coating with which the materials can be coated. However, there is no satisfactory solution for various line materials and aluminum in the prior art to solve the aforementioned problem economically and inexpensively and in particular to sufficiently reduce or almost entirely avoid the consequences of corrosion due to the electrochemical voltage potentials between the contact materials .

From the field of connection technology, a solution for improving said problems for a mechanical connection, namely a screw, is proposed in WO 2013083540 A1. Such a screw has, on the one hand, sufficient strength and, on the other hand, adequate corrosion resistance. Advantageously, the material of the screw can in particular be resistant to contact corrosion with carbon or carbon-reinforced composite materials. Since carbon is unfavorable to iron due to its electrochemical potential, it is It is particularly important for the permanent use of the screw that this type of corrosion is avoided, regardless of whether the environment is also corrosive or not. The screw can advantageously consist of a highly heat-resistant material in accordance with EN 10269 or similar, in particular of an austenitic material or of a nickel-based alloy.

Such material pairings are not suitable for the transmission of electrical power and high currents. Rather, contact corrosion also has the disadvantageous effect that the transition resistance in the area of the contact surfaces of the contact partners changes, in particular increases, and the contact point is then increasingly heated. This sometimes leads to considerable consequential damage, such as a fire.

A large number of solutions can be found in the prior art, but these cannot be transferred to electrical connecting means. In WO 1995000678A1, for example, a method for producing corrosion-protected metallic materials by passivation is described, in which a layer of an intrinsically conductive polymer is applied to the metallic material and the coated metallic material is brought into contact with oxygen-containing water until equilibrium potential is reached , polyaniline in particular being used as the conductive polymer. The conductivity achieved is not sufficient for the transfer of electrical energy and aluminum cannot be treated accordingly either.

Basically, aluminum oxide layers cause considerable problems when connecting contact parts or busbars made from aluminum material. In addition to the above-mentioned problem of increased resistance, there are also the problems that in the surface contact areas, so to speak, there are gaps and voids into which there are Can store foreign materials, which in turn form corrosion nuclei and increase the problem even further.

In the field of vehicle construction, however, increasingly light materials are required and recent, well-known examples of product recalls by vehicle manufacturers show that the problem still exists and has not been adequately solved. Even the known PVD and CVD processes have so far not been able to deliver convincing results for applications in electrical connection materials, busbars, power distributors and battery terminals. The invention is therefore based on the object of overcoming the aforementioned disadvantages in the prior art and of providing an inexpensive, corrosion-resistant connection structure and a corresponding method for providing such a structure.

This object is achieved by the combination of features according to claim 1.

A basic idea of the invention is to design a specific structure in which a connection zone takes place between a first and second inner layer of two connection partners, which were produced by means of cold gas spraying. According to the invention, an electrical connection structure for use as a means of transmitting electrical energy between a first and second electrical component, the connection structure being formed from several layers arranged in series with one another, a first outer layer made of aluminum or an aluminum alloy and a second outer layer preferably made of aluminum or an aluminum alloy and wherein a third and preferably fourth layer, namely one or two inner layers between the outer layers Layers are provided, the inner or inner layers 30 being each produced by cold gas spraying. This results in a material composite which has particularly good corrosion properties. Alternatively, however, as indicated, only one aluminum or an aluminum alloy -Layer can be provided and any combination with e.g. other materials such as Cu-Al.

The same applies to the specified cold gas layers. It would also be conceivable to provide only one inner cold gas layer on one aluminum or one aluminum alloy layer. In the case of applications, such as applications with a combination of copper or copper alloys as a connection partner, only one cold gas layer would therefore be required.

A preferred embodiment of the invention provides that the two inner layers are connected directly to one another in a contacting manner (i.e. without further layers in between).

Another preferred embodiment of the invention provides that the electrical connection structure is designed as a connection structure that is detachable between at least two of the four layers and that can be separated from a connection position (connected state) to a disconnected position (pre-assembly state or disconnected state) and corresponds to these the contact surfaces are designed so that they form a non-positive and / or positive connection in the non-separated connection position. In these designs, the two connection partners can therefore be as intended from one another (formed from aluminum or separated, similar to a connector that is connected or can be separated for plugging and unplugging.

In order to produce a permanently corrosion-protected connection, the two connection partners can accordingly be brought into contacting system with their anti-corrosion layers produced by means of cold gas spraying in order to then act as an electrical connection, for example between two devices or an electrical energy source and an electrical energy sink.

An alternative embodiment of the invention provides that the electrical connection structure is designed as a non-detachable, in particular material-locking connection structure in which the two inner corrosion protection layers are held together by atomic or molecular forces.

In the alternative embodiment of the invention described above, in which a non-positive connection is provided, it is provided that a connecting means runs through all layers (viewed in the direction of energy flow with current flow), in particular a connecting bolt and for this purpose in each layer, in order to establish the non-positive connection an opening is provided through which the connecting bolt penetrates.

The structure of the arrangement is designed in such a way that the second inner layer was applied to the first outer layer by means of cold gas spraying, in particular it completely covered up to the edge area and that the third inner layer was applied to the second outer layer, in particular this, by means of cold gas spraying also completely covered to the edge area.

The connection partners formed in this way can form a completely or at least partially corresponding contact surface for the electrical connection. The areas can preferably be of the same size, but a partial contact system would only be possible from a partial area.

It is also advantageous if the two outer layers in their direction of thickness (in the serial direction of the serially arranged layers) have a slight has a significantly greater thickness than the inner layers, in particular in a ratio greater than 1:10. In other words, this means that a comparatively thick layer-like structure is formed in each case by the aluminum or aluminum alloy, onto which a comparatively thin layer, namely as a functional corrosion protection layer, is sprayed in the cold gas spraying process. The optimal material and thickness pairing is tailored to the respective application. If, in addition, a particularly high mechanical strength is required, the outer layers or structures can be made correspondingly thick and solid. This can in particular also bring advantages with regard to the thermal properties of the electrical connection structure and the desired heat transport when used with high currents.

In this respect, the concept of the invention is particularly suitable for realizing a busbar or a power distributor between at least two lines, each of the two connection partners being connected to an electrical line that leads to an energy source or sink, such as for example to a battery or an electrical consumer.

In addition to the connection structure as such, a further aspect of the present invention also relates to the method for producing such an electrical connection structure with the following steps: a) Providing two outer layers or layer-like structures made of aluminum or an aluminum alloy (e.g. Al / Cu alloy); b) applying a corrosion protection layer by means of cold gas spraying onto the respective surface of the two outer layers or structures; c) Joining the two anti-corrosion layers for production a connection structure by forming a series of layers arranged one behind the other in the connected state.

This method is also advantageous if a force-fit connection, form-fit connection and / or material connection is established in step c).

Other advantageous developments of the invention are characterized in the subclaims or are shown in more detail below together with the description of the preferred embodiment of the invention with reference to the figures.

Show it:

1 shows a schematic representation of an electrical connection structure in a pre-assembly state (disconnected state);

2 shows a first exemplary embodiment of an electrical connection structure in a non-positively connected state;

Fig. 3 shows an alternative embodiment of an electrical connec tion structure in a positively connected state and

4 shows a further alternative embodiment of an electrical connection structure in a materially connected state.

The invention is explained in more detail below with reference to FIGS. 1 to 4, the same reference numerals indicating the same structural and / or functional features.

In Fig. 1 is an exemplary schematic representation of an electrical see connection structure 10 shown in a pre-assembly state (disconnected state). The two connection partners 10a, 10b shown form the connection structure 10 in the connected state.

The exemplary embodiments shown in FIGS. 2 to 4 each show a schematic view of an electrical connection structure 10 for use as a means of transferring electrical energy between a first and second electrical component (which is not shown in more detail here).

As can be seen well in the figures, the connecting structure 10 is formed from several layers 20, 30, 40, 50 arranged in series with one another. The layers 20, 30, 40, 50 are briefly explained below.

The bottom layer represents a first outer layer 20, while the top layer represents a second outer layer 50. The two outer layers 20, 50 could also be designed as layer-like structures.

These layers 20, 50 or structures 20, 50 are formed from aluminum or an aluminum alloy.

As can be seen in FIG. 1, on each of the two layers 20, 50 there is a corrosion protection layer 30, 40 produced by cold gas spraying, which lie against one another in the connected state according to FIGS. 2 to 4 and then form inner layers 30, 40.

Fig. 2 shows an embodiment of an electrical connection struc ture 10 produced via a non-positive connection, for which a connecting means 60 runs through all layers 20, 30, 40, 50, in particular a connecting bolt 60, which by means of a nut 61 on the upper and lower outer structure 20, 50 is attached.

In each layer or structure there is a corresponding opening through which the connecting bolt 60 penetrates. 3 shows an exemplary embodiment of an electrical connection structure 10 produced via a form-fitting connection, for which a structural element 11 and a corresponding structural element 51 are provided on the respective outer structures or layers 20, 50. These interlock positively.

4 shows an exemplary embodiment of an electrical connection structure 10 produced via a material or material connection, for which purpose the two inner layers 30, 40 were connected to one another by a corresponding material connection method. The implementation of the invention is not restricted to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the solution shown even in the case of fundamentally different designs. Thus, the materials mentioned in claim 1 can also include other metallic materials without these being mentioned in all possible combination forms in the description. In particular, copper and copper alloys are also included.

Claims

1. Electrical connection structure (10) for use as a means of transmitting electrical energy between a first and second electrical component, the connection structure (10) being formed from several layers (20,30,40,50) arranged in series with one another, one first outer layer (20) made of aluminum or an aluminum alloy and a second outer layer (50) preferably made of aluminum or an aluminum alloy and a third and preferably fourth layer (30, 40), namely one or two inner layers Layers between the outer ones

Layers (20, 50) are provided, the inner or the inner layers (30, 40) each being produced by cold gas spraying.

2. Electrical connection structure (10) according to claim 1, characterized in that the two inner layers (30, 40) are connected to one another in a contacting manner.

3. Electrical connection structure (10) according to claim 1 or 2, characterized in that the electrical connection structure (10) is designed as a connection structure which can be detached between at least two of the four layers (20, 30, 40, 50) can be separated from a connection position to a separation position and their contact surfaces are designed so that they form a non-positive and / or positive connection in the non-separated connection position.

4. Electrical connection structure (10) according to claim 1 or 2, characterized in that the electrical connection structure (10) is designed as a non-detachable, in particular material-locking connection structure. 5 Electrical connection structure (10) according to claim 3, characterized in that a connecting means runs through all layers (20, 30, 40, 50) to produce a force-fit connection, in particular a connecting bolt and an opening is provided in each layer for this purpose through which the connecting bolt penetrates.

6. Electrical connection structure (10) according to one of the preceding claims, characterized in that the second inner layer

(30) was applied to the first outer layer (20) by means of cold gas spraying, in particular covering it completely up to the edge region.

7. Electrical connection structure (10) according to one of the preceding claims, characterized in that the third inner layer (40) was applied to the second outer layer (50) by means of cold gas spraying, in particular covering it completely up to the edge region.

8. Electrical connection structure (10) according to any one of the preceding claims, characterized in that the two outer layers (20, 50) in their thickness direction (in the series direction of the serially arranged layers) has a significantly greater thickness than the inner layers, in particular in the Ratio greater than 1:10.

9. Electrical connection structure (10) according to one of the preceding claims, characterized in that it is designed as a busbar or power distributor between at least two lines and each of the outer layers (20, 50) has a connection management leads.

10. A method for producing an electrical connection structure (10) according to one of the preceding claims, with the following steps: d) providing two outer layers or layer-like structures (20, 50) made of aluminum or an aluminum alloy; e) applying in each case a corrosion protection layer (30, 40) by means of cold gas spraying onto the respective surface of the two outer layers (20, 50) or structures; f) connecting the two corrosion protection layers (30, 40) to produce a connecting structure (10) by forming a series of layers arranged one behind the other in the connected state.

11. The method according to claim 9, characterized in that the connection in step c) is established as a force-fit connection, form-fit connection and / or material connection.