WO2008145453A1

WO2008145453A1 - Motor vehicle power conductor

Info

Publication number: WO2008145453A1
Application number: PCT/EP2008/054599
Authority: WO
Inventors: Adelheid Mertel
Original assignee: Auto-Kabel Managementgesellschaft Mbh
Priority date: 2007-05-30
Filing date: 2008-04-16
Publication date: 2008-12-04
Also published as: DE102007025268B4; DE102007025268A1

Abstract

The invention relates to a motor vehicle power conductor, in particular a motor vehicle battery conductor, having a first conductor element which is formed essentially from aluminium. In order to make electrical contact with a second conductor element, it is proposed that the first conductor element have a metal surface, which is applied by means of cold gas spraying, at least in places in the area of an electrical contact point with a second conductor element.

Description

Motor vehicle power conductor

The application relates to a motor vehicle power conductor, in particular a motor vehicle battery ladder with a first part conductor formed essentially of aluminum. Furthermore, the application relates to a method of such a motor vehicle power conductor.

Motor vehicle power conductors, in particular motor vehicle battery conductors as well as generator conductors and other conductors, are characterized by large cross sections and high current carrying capabilities. In the past, automotive battery leads were preferably made of copper. However, due to cost and weight saving measures, it is increasingly necessary to manufacture aluminum automotive power conductors. When using aluminum, however, the contacting of two sub-conductors of a motor vehicle power ladder is problematic. On the aluminum surface, an aluminum oxide forms, which negatively influences the conductivity. Due to the aluminum oxide layer, a mechanical connection between two partial conductors is associated with a high contact resistance, so that mechanical connections are generally not usable. For this reason, it has gone over to producing contact points by means of soldering or welding. However, these contacting methods are expensive. Furthermore, since these are cohesive compounds, they can not easily be separated again. Because of these disadvantages, the task arose to provide a motor vehicle power ladder available, in which contact points between Aluminiuπiteilleitern have a low contact resistance.

The object indicated above and derived from the prior art is achieved in that the first sub-conductor has at least partially in the region of an electrical contact point with a second sub-conductor a metal surface applied by means of cold gas spraying.

It has been recognized that thin metal surfaces can be applied to an aluminum conductor by cold gas spraying in a particularly simple manner. In cold gas spraying, a powdered spray material can be accelerated by means of an inert gas onto a surface. The acceleration is preferably carried out in a Lavaic nozzle, wherein the powdered spray material is preferably accelerated to supersonic speed. The impact energy of the pulverulent metal particles breaks up the aluminum oxide layer and creates a direct connection between the aluminum of the partial conductor and the metal powder, which is applied by means of cold gas spraying. The kinetic energy released on the surface when the metal particles strike the surface causes the materials to heat up to a limited extent, creating a cohesive connection. The metal surface thus applied is well suited for the contacting of two partial conductors, at least one of which is made of aluminum. According to a preferred embodiment, it is proposed that the electrical contact point is formed as a solder joint. It is possible that in the region of the contact point, the sub-conductors are soldered together.

Particularly advantageous is the application of a metal surface on a sub-conductor, when the second sub-conductor is also formed of aluminum. In this case, it is particularly preferred if along the contact point both the first and the second sub-conductor is equipped with the metal surface applied by means of cold gas spraying. In this case, a contact between the sub-conductors along the contact point can be made possible, wherein the contact resistance is dependent on the metal used.

In order to achieve the lowest possible contact resistance, it is preferred that the metal surface is formed from a non-ferrous metal, in particular copper, zinc, tin, silver, gold or an alloy thereof. In particular, metals which have a low tendency to form oxide layers are well suited to the production of a metal surface.

In addition to a cohesive solder joint is also preferred that the electrical contact point is formed as connectors. Since a metal surface with a good electrical conductivity is applied along the contact point, it is possible to dispense with a substance-bonding connection. This makes it possible to provide connectors of electric battery ladders made of aluminum, which are simple and inexpensive to manufacture. To equip the connector with good electrical properties, it is proposed that the first sub-conductor in the region of the mating face of the connector has the metal surface applied by means of cold gas spraying. Particularly in the area of the mating face, which area comes in direct mechanical contact with the second sub-conductor, a metal surface is necessary which exhibits low inclinations to oxidize or has a high conductivity.

To secure the connectors against mechanical loads, it is proposed that this is designed as PressVerbindung. In this case, the connector can be solved only with an increased effort.

In the field of vehicle construction, the use of flat conductors is increasingly required, in particular as flat conductors show advantages over round conductors during installation. For this reason, it is proposed that the first and / or the second part conductor are flat conductors.

To produce a plug connection, it is necessary that the second sub-conductor is inserted into the first sub-conductor or vice versa. In order to ensure this, it is proposed that the second sub-conductor has a blind groove corresponding substantially to the cross-section of the first sub-conductor, and the first sub-conductor has the metal surface applied by means of cold-gas spraying in the region which can be accommodated by the blind groove. It is also possible that in the region of the blind groove, on the inner wall of the first sub-conductor, also a metal layer was applied by means of cold gas spraying. With the presented connector, it is possible to insert the second sub-conductor in the blind groove of the first sub-conductor. It is also possible that at least one spring element is provided in the region of the blind groove, which is deformed by the insertion of the second conductor into the blind groove and against the surface, preferably pressed against the surface of the mating face of the second conductor. This provides a connector with good electrical and mechanical properties.

Since the metal, which is applied in the region of the contact point on the surface of the conductor, is often nobler than aluminum and therefore more expensive, the layer thickness of the metal surface should be thin. It is therefore preferred that the layer thickness is between 2 00 / μm and 500 / μm, preferably 350 / μm.

In addition to the solder and the connector is also proposed that the electrical contact is formed as a screw connection. For example, it is possible that a connecting bolt is screwed to a flat conductor. The connecting bolt may be shaped such that a part insertable into a hole of a flat conductor has a smaller cross-section than the rest of the bolt. The introduced into the bore part may be provided with a thread through which the bolt can be screwed to the flat part. This can be done by a screw on an internal thread in the bore or by a nut which is screwed onto the underside of the conductor to the thread. The surface which makes contact with the bolt on the upper side of the flat conductor can be referred to as be formed electrical contact point in the sense of the application. Thus, it is possible, for example, that a copper stud can be electrically contacted with an aluminum flat conductor in a simple manner. By applying the metal surface along the electrical contact point is achieved that in addition to the good electrical properties, a high mechanical strength is achieved. This prevents the bolt from being pulled into the material of the flat conductor when the nut is tightened.

A further subject matter is a method for producing a motor vehicle power conductor with forms of a first partial conductor of aluminum and cold gas spraying of a metal surface in the region of an electrical contact point with a second partial conductor.

The article will be explained in more detail with reference to drawings showing an exemplary embodiments.

In the drawing show:

Fig. 1 is a first contact point at a

Butt joint between partial conductors;

FIG. 2 shows a second contact point with an overlapping connection between partial conductors; FIG.

3 is a contact point when connected to a contact pin,

Fig. 4 is a plug connection between sub-conductors.

Fig. 1 shows a first conductor 2 with an electrical contact point 4 and a second Subconductor 6. In the area of the electrical contact point 4, the surface of the first subconductor 2 is by means of

Cold gas spraying applied with a copper layer.

During cold gas spraying, this copper layer is bonded cohesively to the aluminum of the first partial conductor.

In the region of the end face of the second partial conductor 6, a metal surface made of copper can likewise be applied by means of cold gas spraying. The end faces of the sub-conductors 2, 6 can then be easily soldered together. It is also possible that the end faces of the sub-conductors 2, 6 are brought into frictional connection with one another. Due to the coating with a copper surface, a high electrical conductivity is achieved in the region of the transition.

FIG. 2 shows a further possibility for electrically connecting a first sub-conductor 2 to a second sub-conductor 6. In contrast to FIG. 1, the sub-conductors 2, 6 overlap in the region of the electrical contact point 4. In the region of the electrical contact point 4, both the first sub-conductor 2 and the second sub-conductor 6 can be coated by means of a copper surface. This is applied by cold gas spraying. The layer thickness of the surface is preferably 350 / μm. The sub-conductors 2, 6 can be soldered. Since the electrical contact point 4 is formed of copper, it is not necessary to protect the soldering surface from environmental influences, as there is a copper-copper compound at the transition point and the formation of aluminum oxide in this area is impossible. Fig. 3 shows the second sub-conductor 6 as a connecting bolt, for example for a

FremdstartStützpunkt or for another electrical tap within the electrical system of a motor vehicle. The bolt 6 has at its end a pin which may be provided with a thread 8. The pin is shaped so that it fits into a bore 10 of the first sub-conductor 2. The bolt 6 is screwed with its thread 8 either in the bore 10 or the thread 8 protrudes from the conductor 2 at the bottom out. In this case, the bolt 6 can be screwed with a nut on the sub-conductor 2. In the region of the electrical contact point 4, the first sub-conductor 2, which is formed from aluminum, has been coated with a copper surface by means of cold gas spraying. The bolt 6 may be formed of copper. When screwing the bolt 6 on the first conductor 2, a contact surface in the region of the electrical contact point 4, which represents a copper-copper transition. This transition is characterized by a low electrical contact resistance. When screwing the bolt 6 is pressed against the conductor 2. By applying the copper surface along the electrical contact point 4, the mechanical strength is increased in this area, thereby preventing that the bolt 6 is screwed into the material of the first sub-conductor 2.

4 shows a plug connection between a first sub-conductor 2 and a second sub-conductor 6. The second sub-conductor 6 has a blind groove 12 on its end face. The interior of the blind groove 12 can be coated, for example by means of cold gas spraying, with a copper surface. It is also possible that 12 spring elements 14 are provided within the blind groove. These spring elements 14th are preferably formed on the lower or upper inner wall of the blind groove 12. However, the spring elements may also be provided on the side walls of the blind groove 12.

To the spring elements 14 corresponding electrical contact points 4 are provided on the first sub-conductor 2. These electrical contact points 4 have been coated with a copper surface by means of cold gas spraying. It is also possible, but not shown, that the first sub-conductor 2 has been completely coated with a copper surface in the region which has been inserted into the blind groove.

If the first sub-conductor 2 is inserted into the blind groove 12, the spring elements 14 are tensioned and press with their spring force on the electrical contact point 4. At least via the spring elements 14 an electrical contact between the second sub-conductor 6 and the first sub-conductor 2 is made possible. The spring elements 14 allow not only the electrical contacting but also a mechanical attachment of the first sub-conductor 2 in the blind groove 12.

The proposed coating of the electrical contact point with a metal surface by means of cold gas spraying enables improved electrical contacting between partial conductors made of aluminum of a motor vehicle power conductor. The presented compound is characterized by a low contact resistance, cost-effective production and resistance to environmental influences.

Claims

PATE NT TO SP RU CHE

1. motor vehicle energy ladder, in particular motor vehicle battery ladder, with a first substantially made of aluminum sub-conductor (2), characterized in that the first sub-conductor {2) at least partially in the region of an electrical contact point (4) with a second sub-conductor (6) by means of

Cold gas spraying has applied metal surface.

2. motor vehicle power conductor according to claim 1, characterized in that the electrical contact point

(4) is formed as a solder joint.

3. Motor vehicle power conductor according to one of the preceding claims, characterized in that the second sub-conductor (6) is formed of aluminum.

4. motor vehicle power conductor according to one of the preceding claims, characterized in that the second sub-conductor (6) at least partially in the region of the electrical contact point (4) has a metal surface applied by means of cold gas spraying.

5. motor vehicle power conductor according to one of the preceding claims, characterized in that the metal surface is formed from a non-ferrous metal, in particular copper, zinc, tin, silver, gold or alloys thereof.

6. motor vehicle power conductor according to one of the preceding claims, characterized in that the electrical contact point (4) is formed as a plug connection.

7. motor vehicle power conductor according to one of the preceding claims, characterized in that the first sub-conductor (2) in the region of the mating face of the connector has the metal surface applied by means of cold gas spraying.

8. motor vehicle power conductor according to one of the preceding claims, characterized in that the plug connection is a press connection.

9. motor vehicle power conductor according to one of the preceding claims, characterized in that the first and the second sub-conductor (6) are flat conductors.

10. Motor vehicle power conductor according to one of the preceding claims, characterized in that the second sub-conductor (6) has a substantially the cross-section of the first sub-conductor (2) corresponding to the first sub-conductor (2) receiving blind groove (12), and that the first sub-conductor ( 2) in the area which can be accommodated by the blind groove (12) has the metal surface applied by means of cold gas spraying.

11. Motor vehicle power conductor according to one of the preceding claims, characterized in that the applied by means of cold gas spraying metal surface has a layer thickness of between 200μm and 500μm, preferably 350μm.

12. Motor vehicle power conductor according to one of the preceding claims, characterized in that the electrical contact point (4) is formed as a screw connection.

13. Motor vehicle power conductor according to one of the preceding claims, characterized in that the second sub-conductor (6). a connecting bolt is.

14. Motor vehicle power ladder according to one of the preceding claims, characterized in that the connecting bolt is electrically connected at least in the region of the contact point (4) with the first sub-conductor (2).

15. A method for producing a motor vehicle power conductor with

Forming a first partial conductor (2) made of aluminum, cold gas spraying of a metal surface in the region of an electrical contact point (4) with a second partial conductor (6).