Current-carrying contact element with structured contact surface

Abstract

To provide a contact element achieving the conditions of low connection resistance and long-term stability.SOLUTION: A contact element includes: a base body 102 having a structured contact surface that has a plurality of collecting recesses 120 for receiving oxide between a plurality of contact protrusions 104 projecting in a contact direction 200, each contact protrusion 104 having a contact point 106 for contacting a conductor at the contact point; and a nickel layer applied to the structured contact surface for hardening the contact protrusions so that the coated contact protrusions break an oxide layer on the conductor to be contacted upon connection to the conductor to expose a bare mating contact point, and for sealing the contact points and the bare mating contact points against oxygen. The ratio of the width (b) at a base 103 of the contact protrusion to the height (h) of the contact protrusion is 2 or more and 10 or less.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The subject matter described herein generally relates to current-carrying contact elements having at least one structured contact surface and methods of manufacturing such current-carrying contact elements. [Background technology]

[0002] In power supply networks and on-board electrical systems of electric vehicles, different conductor and / or coating materials often come into contact with each other when connecting different components. Aluminum is preferred over copper due to its low density and relatively high electrical conductivity, as well as its high availability and low price. For users, this lightweight material presents challenges in terms of contact and long-term behavior.

[0003] Previously, aluminum-silver and aluminum-copper intermetallic phases have been investigated as the primary cause of failure in unbonded current carrying connections involving the corresponding material combinations, however the observed increase in resistance cannot be fully explained by the growing phases.

[0004] In particular, the contact resistance increases due to oxidation. When connecting conductors, for example the busbar 1000 shown in Fig. 17, before each new contact process the surface must be treated to remove the oxide layer 1100. For example, a wire brush is used to clean the aluminum or copper surface from the oxide layer. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem is therefore to solve the above problems. In particular, the problem is to reduce the effort required for contact. Time-consuming and costly preparatory procedures should be minimized. Another problem is to ensure that the contact is stable over time. A further problem is to ensure that the quality of the contact remains constant with repeated contacts. [Means for solving the problem]

[0006] The above problem is solved by the subject matter of the independent patent claims. Advantageous further embodiments are the subject matter of the dependent patent claims.

[0007] According to one general aspect, a current-carrying contact element solves the above problem. The contact element has a contact protrusion that includes a nickel layer, which is harder than the aluminum of the conductor, and thus the contact protrusion can break the oxide layer of the conductor it contacts to form a metal contact. In relation to the soft aluminum located below the oxide layer, the hard nickel causes the softer aluminum to flow, which breaks the oxide. This results in a good contact (contact resistance less than 5 μΩ). In addition, the nickel layer allows for long-term stability, since the nickel can unexpectedly seal the bare mating contact against oxygen, so that a new oxide layer cannot grow. The special dimensions of the contact protrusions allow low connection resistance and long-term stability conditions to be achieved, especially when opposing conductors are pressed against each other, since the contact protrusions withstand the contact pressure and meet the resistance requirements along the electrical path.

[0008] A first aspect relates to a current-carrying contact element having at least one contact surface, in particular two opposite contact surfaces, which electrically contacts two opposing electric conductors in a contact direction. The two conductors are joined to one another, i.e. moved towards one another in a contact direction, so that the contact element is subjected to a compressive force in the contact direction. The conductors can be joined, for example, by a screw or a clamp. In other words, the pressure is applied perpendicularly to the contact surface of the contact element. The contact element can also be formed integrally with one of the conductors. In other words, the contact surface of the contact element contacts the conductor. In other words, the conductor comprises a contact element at one end.

[0009] The current-carrying contact elements can also be referred to as current-carrying contact fastening elements. Contact elements must be distinguished from thread locks, which are intended to prevent unintentional loosening or loosening of the threaded connection, since the thread locks are disposed between the screw head and the element they contact. Like the thread locks, the contact elements are intended to prevent unintentional deterioration of the connection. In addition to the properties of ensuring long-term contact, the contact elements can optimize electrical connection properties and minimize preparation steps, as explained below.

[0010] In particular, the contact element comprises or consists of a base body having at least one structured contact surface. Both opposing contact surfaces may be structured. In this context, a structured contact surface is understood to be a surface that is machined by a machining process such as embossing, etching, milling, etc., to form structures having a defined shape. It is advantageous for both opposing contact surfaces of the base body to be structured.

[0011] The defined shape of the structured contact surface is a number of collection recesses between a number of contact protrusions that protrude in the contact direction. For example, the collection recesses can be formed by pressing the contact surface. This allows for a cost-effective process for forming the depressions and protrusions, since only one process step is required for structuring and the pressing die (also called punch) can be used repeatedly. Alternatively, of course, a subtractive process may be used, which may allow a higher precision compared to embossing, but is usually also more expensive, for example because of the masking and etching steps required.

[0012] The structure allows the oxide removed from the contacting conductor to be absorbed in the recess, and a contact is provided on each contact protrusion to contact the conductor at the contact. The structure is therefore optimized for two issues: the contact is as large as possible across the surface to minimize contact resistance. Furthermore, the recess is designed to provide enough space to completely absorb the removed oxide. Therefore, the recess is usually deeper than it is wide.

[0013] The exact shape of the depression is determined by the manufacturing process. For example, the embossed depression is in the shape of a triangular prism. In other words, in a cross section perpendicular to the contact surface, the depression has a triangular shape, the angle of the collection depression between the surface normal of the contact surface and the edge of the collection depression is less than or equal to 45°, preferably less than 30°, most preferably less than 10°, in particular the structure is formed by embossing.

[0014] For example, if the manufacturing process is an etching process, the recess may be a groove, i.e., a generally rectangular shape in cross section perpendicular to the contact surface, with the aspect ratio of the width to the depth of the rectangle being 0.05 to 0.15. During milling, any shape can be formed with a perimeter that forms a polygon.

[0015] Furthermore, the contact element comprises a nickel layer applied to the structured contact surface. The nickel layer can be applied, for example, using an electroplating process. Here, a base body made of a highly conductive material such as aluminum or copper is nickel plated to enable two effects described below. It should be noted that a body made entirely of nickel achieves the same effect, but is less conductive and therefore has a higher connection resistance than a body made of copper with only a nickel layer applied. In this specification, a nickel layer is defined as a layer containing nickel. For example, the nickel layer may consist of only nickel. However, the nickel layer may also contain a nickel compound, such as NiP. The mass fraction of nickel in the layer is preferably 50% or more, particularly preferably 75% or more, and even more preferably 90% or more.

[0016] The nickel layer allows the contact bump to be hardened so that the coated contact bump, upon connection with a conductor, breaks open the oxide layer of the contacting conductor (usually made from a more conductive material such as aluminum or copper) and exposes the bare mating contact. The nickel layer therefore allows the preparation steps to be minimized, as the surface of the contacting conductor does not need to be removed and the mating contact is exposed during the bonding step.

[0017] The nickel layer also provides a fine seal between the contact and the bare mating contact against oxygen. Surprisingly, nickel has better properties than, for example, silver. This unexpected sealing contact formation allows the connection to remain stable over a long period of time.

[0018] The significantly higher melting and recrystallization temperatures of nickel compared to silver and tin result in no adhesion between the contact element and the mating contact when disconnected. For tin- and silver-plated surfaces, cold welding, as would be expected due to the higher operating temperatures, can damage the coating of the contact element when loosened and impair reassembly.

[0019] The contact protrusions can form bump-shaped (hereinafter also called rod-shaped) contact pins protruding in the contact direction. The term pin is used here mainly to describe elongated objects with a constant, for example circular, square or polygonal cross section. In this case, the cross-sectional dimension is greater than the length. Alternatively, the contact protrusions can form lamellar contact blades protruding in the contact direction. Lamellar is the term for ribs that are repeated in the structure, which always have the same form, i.e. periodic structures.

[0020] The base of the contact protrusion is defined here as the deepest point of the structure. For example, this is the depth of the embossing, etching, milling, etc. The width of the contact pin is the diagonal. In the case of a circular cross section, the width of the contact pin is the diameter. The width of the contact blade is the distance between the two sides of the blade in the direction of the structure with a repeating form. In both cases, the width is measured perpendicular to the contact direction, i.e. parallel to the contact surface. During embossing, the width of the contact protrusion results from the width of the pattern of the embossing mold, which structures the contact protrusion as the embossing is performed in the contact direction.

[0021] The height is equal to the depth to which the structure is formed. As mentioned before, this size depends on the width of the contact bump and is achieved by the process selected. For example, it is defined by the force with which the embossing die is applied, the time the etching is performed or the hardness of the contact element.

[0022] It has been found that the ratio between the width of the base of the contact protrusion and the height of the contact protrusion must be greater than or equal to 2 in order for the protrusion to be stable enough to withstand the contact pressure when the conductors are pressed together. In other words, above this ratio, the oxide layer will collapse first and the contact protrusion will be stable. It has also been found that the ratio between the width of the base of the contact protrusion and the height of the contact protrusion must be less than or equal to 10 in order to transmit a sufficient force to the oxide layer to break it. If the ratio is greater than this, not enough force will be transmitted to the contact and the oxide layer will not be absorbed in the collection recess and will remain at the contact location and / or the contact will not be sealed by the remaining oxide layer.

[0023] According to a preferred embodiment, the ratio between the width of the base of the contact projection and the height of the contact projection is greater than or equal to 3. A ratio of greater than or equal to 4 is particularly preferred.

[0024] According to a further preferred embodiment, the ratio between the width of the base of the contact projection and the height of the contact projection is less than or equal to 8. A ratio of less than or equal to 6 is particularly preferred.

[0025] According to a second embodiment, in addition to the first embodiment, the base body has a through opening connecting the two contact surfaces. The through opening is preferably formed before structuring. The through opening allows a fastening means, such as a screw, to pass through the contact element. This allows the conductors to be pressed against each other with a predefined force, which can be defined by the fastening means. This allows the contact protrusion to transmit a force sufficient to break the oxide layer of the conductor, so that the contact protrusion does not deform and allows repeated use of the contact element, while the nickel layer seals the counter contact and allows long-term contact. The through opening is formed first and then structured. Due to the smaller surface area that has to be deformed during embossing, the surface pressure can be increased with the same force and therefore a better structure can be achieved.

[0026] The through openings advantageously have a diameter of more than 0.5 cm and / or less than 1.5 cm, which means that standard screws of sizes M5 to M15 can be used.

[0027] According to a third aspect, in addition to one of the above aspects, the distance between two adjacent contacts is 0.5 mm or more and / or 1.5 mm or less. The shorter the distance, the more recesses there are to accommodate oxides. The larger the distance, the fewer contacts that need to be sealed. It is preferred that the distance between two adjacent contacts is 0.75 mm or more and / or 1.25 mm or less.

[0028] According to a fourth aspect, in addition to any of the above aspects, the plurality of contact protrusions includes at least three adjacent contact pins, and to allow for an asymmetric arrangement of the contacts, a first distance between a first contact of a central contact pin and a first adjacent contact of a first adjacent contact pin is not equal to a second distance between the central contact and a second adjacent contact of a second adjacent contact pin. This arrangement allows the oxide layer to be broken open at multiple new points on the conductor during new contact (during which the contact elements are typically slightly displaced), thus allowing for continuous breaking open of the oxide layer.

[0029] According to the fifth embodiment, in addition to the second and fourth embodiments, adjacent contact pins are arranged on a radius connecting the through-opening and the edge of the connection fastening device. The contact elements rotate around the through-opening, and therefore it is sufficient to break this axis of symmetry to ensure that the oxide layer is continuously broken during repeated connections. This simplifies the design of the mask, for example the punching die, and allows to increase the number of contact projections per surface.

[0030] It is particularly preferred that the first distance is ≧0.5 mm and ≦1.5 mm and / or the second distance is ≧1.5 times the first distance.

[0031] According to the sixth aspect, in addition to the second aspect, the plurality of contact protrusions includes at least two adjacent contact blades, and in order to allow an asymmetric arrangement of the contacts, the contact blades do not form a circular line around the through opening, but a radius starting from the through opening, which allows the same effect as in the fifth aspect. It is particularly preferred that the distance between two adjacent contacts of the contact blades is 0.5 mm or more and / or 1.5 mm or less.

[0032] According to the seventh aspect, in addition to the second to sixth aspects, the structured contact surface around the through opening is a ring having a width of 0.2 cm or more and / or 5 cm or less. The lower limit of the ring width is necessary to create a sufficient contact surface. The upper limit facilitates increasing the contact force per surface area. Rings having a width of 1 cm or more and / or 2 cm or less are particularly preferred.

[0033] According to an eighth embodiment, in addition to one of the above embodiments, the material of the base body includes aluminum and / or copper. This can increase the electrical conductivity of the base body. For stability, it is advantageous for the base body to have a thickness of at least 1 mm or more. Additionally or alternatively, to enable a compact design, the thickness of the base body may be 5 mm or less.

[0034] According to a ninth aspect, in addition to one of the above aspects, the height of the contact protrusion may be 0.01 mm or more and / or the height of the contact protrusion may be 1 mm or less. A smaller height of the contact protrusion may facilitate easier manufacturing. A larger height makes it easier to accommodate a larger amount of oxide in the recess, and therefore keeps the recess free, even with repeated use. It is particularly preferred that the height of the contact protrusion is 0.05 mm or more and / or that the height of the contact protrusion is 0.5 mm or less. It is even more preferred that the height of the contact protrusion is 0.075 mm or more and / or that the height of the contact protrusion is 0.25 mm or less.

[0035] Additionally or alternatively, the nickel layer may have a thickness of 0.1 μm or more and / or the nickel layer has a thickness of 10 μm or less.

[0036] A tenth aspect relates to an electrical connection system comprising a current carrying contact element according to one of the previous aspects and two opposing electrical conductors, the conductors contacting the embossed contact surfaces may comprise aluminum. Preferably, both conductors are made of aluminum and both contact surfaces are embossed. It is particularly surprising that connections made of aluminum and nickel are stable over time. It should be understood that the description of the connection system is not limited to conductors comprising aluminum. Other metals, such as copper and nickel, are also stable over time.

[0037] An eleventh aspect relates to an electrical connection system according to the tenth aspect, further comprising a screw for mechanically connecting the electrical conductors. As mentioned above, the screw allows the transmission of forces to break the oxide layer.

[0038] A twelfth aspect relates to an electrical connection system according to the tenth or eleventh aspects, in which at least one of the electrical conductors is a busbar. Thus, the system can be used in particular in high current applications such as electromobility.

[0039] A thirteenth aspect is a method of manufacturing an energizing contact element according to any of the above aspects, the method comprising: - structuring the base body to form a structured contact surface, the structured contact surface having a number of collection recesses for receiving oxide and a number of contact protrusions for contacting conductors; Coating the structured, in particular embossed, contact surface with nickel to form a nickel layer, which is intended to harden the contact projections, so that the coated contact projections destroy the oxide layer of the conductor they contact when connected to the conductor. Including, wherein the ratio of the width (b) of the base of the contact projection to the height (h) of the contact projection is 2 or more and 10 or less.

[0040] For further details, see the above description of embodiments 1-12.

[0041] A fourteenth aspect relates to the method according to the thirteenth aspect, wherein the structured contact surface of the base body is structured to form collection recesses in a cross section perpendicular to the contact surface, the angle of the collection recesses between a surface normal of the contact surface and an edge of the collection recess being equal to or less than 45°, preferably less than 30°, most preferably less than 10°, in particular the structure being formed by embossing.

[0042] As mentioned above, the collection recess has an approximately triangular shape at its lowest point, also called the base in the following. The side of the collection recess and the normal to the contact surface describe a triangle. A small angle allows to maximize the contact surface and thus reduces the line resistance.

[0043] A fifteenth aspect relates to a method according to the thirteenth or fourteenth aspect, wherein the collection recesses are realised by an embossing process, which is particularly cost-effective.

[0044] Alternatively, a recess can be etched. As previously mentioned, the etched recess often forms a groove. Such a groove can be depicted similarly to the triangle of the fourteenth embodiment, i.e. with the deepest point connected to the side.

[0045] Additionally, the through openings can be formed in the base body prior to embossing.

[0046] In order to better understand the present invention, the present invention will be described in more detail using the examples of embodiments shown in the following drawings. The same parts are indicated with the same reference numerals and the same component names. Furthermore, some features or combinations of features of the different embodiments shown and described can represent independent solutions of the present invention or solutions of the present invention. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 illustrates a connection system according to one aspect. [Diagram 2] FIG. 13 is a top view of a connecting element according to one aspect. [Diagram 3] FIG. 3 shows a detail III of the connecting element of FIG. 2 corresponding to the first example. [Figure 4] FIG. 3 shows a detail III of the connecting element of FIG. 2 corresponding to a second example. [Diagram 5] FIG. 5 is a cross-sectional view taken along the cross-sectional axis VV of FIG. 3 or FIG. 4. [Figure 6] FIG. 2 shows an embossing mold for forming a structured surface of a connecting element according to a first example. [Figure 7] FIG. 7 shows detail U of the embossing mold of FIG. 6. [Figure 8] FIG. 7 is a cross-sectional view taken along the cross-sectional axis AA of FIG. 6. [Figure 9] FIG. 13 shows an embossing mold for forming a structured surface of a connecting element according to a variant of the first example. [Figure 10] FIG. 10 shows detail X of the embossing mold of FIG. 9. [Figure 11] FIG. 10 is a cross-sectional view taken along the cross-sectional axis AA of FIG. [Figure 12] FIG. 13 shows an embossing mold for forming a structured surface of a connecting element according to a second example. [Figure 13] FIG. 13 shows detail V of the embossing mold of FIG. 12. [Figure 14] FIG. 13 is a cross-sectional view taken along section axis AA of FIG. 12. [Figure 15] FIG. 13 shows an embossing mold for forming a structured surface of a connecting element according to a variant of the second example. [Figure 16] FIG. 16 shows a detail W of the embossing mold of FIG. 15. [Figure 17] FIG. 1 illustrates a connection system according to the current art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] In the following, the contact elements are explained with the aid of the drawings: Figure 1 shows an electrical connection system with conductors 1000, 1000' connected in a contact direction in a similar manner to the system of Figure 17. In addition, the system 10 comprises a current carrying contact element 100.

[0049] As shown in Fig. 1, the current-carrying contact element 100 has two opposing contact surfaces 110, 110'. One contact surface 110, 110' is used to electrically contact opposing electrical conductors 1000, 1000'. Contact is made when the opposing electrical conductors 1000, 1000 are moved towards each other in a contact direction 200. As shown in Fig. 1, the contact direction 200 is perpendicular to the surfaces of the two opposing contact surfaces 110, 110'.

[0050] As further shown in FIG. 1 , the contact element 100 has a base body 102 with structured contact surfaces 110, 110′. In particular, a number of contact protrusions 104 protrude from the base body 102 in a contact direction 200. Each contact protrusion 104 has a contact 106 at which it contacts the conductor 1000. The contact 106 should be understood here as a point or surface of the contact element 100 that is electrically connected to a mating contact (not shown) formed on the conductor 1000, 1000′. Electrically connected means that when the contact element 100 is connected to at least one of the conductors 1000, 1000′, an electric current can be passed through the connection between the contact and the mating contact.

[0051] Furthermore, the structured contact surface 110, 110' has a number of collection recesses 120 that do not significantly contribute to the current flow. The collection recesses 120 serve to collect at least a portion of the oxide layer 1100.

[0052] Additionally, a nickel layer (not shown) is applied to the structured contact surfaces 110, 110'. The nickel layer serves to harden the contact bumps 104 so that, upon connection with the conductor 100, the coated contact bumps 104 break open the oxide layer 1100 of the contacting conductor 1000, exposing the bare mating contact (not shown).

[0053] Then, when the two conductors 1000, 1000′ are moved towards each other in the contact direction 200, the contact protrusions 104 break through the oxide layer 1100. Thus, the resistance between the conductors 1000, 1000′ and the contact elements 100 is reduced, since the contacts 106 make direct contact with the bare mating contacts of the conductors 1000, 1000′, rather than making electrical contact through the insulating oxide layer 1100.

[0054] It has been surprisingly found that the nickel layer provides a long-term seal against oxygen between the contact 106 and the bare counter contact, stabilizing the connection over time. Traditionally, nickel has been expected to be inferior to more noble metals such as silver. Thus, long-term is defined relative to comparable contact with silver.

[0055] In order to utilize the above mentioned effect, the contact protrusion 104 is designed as shown in Fig. 2 to Fig. 5. The considerations underlying the structuring of the contact element are, for example, that the effective contact surface, i.e. the sum of the surfaces of the contacts, should be as large as possible. Furthermore, the contacts must transmit a force per surface area sufficient to break through the oxide layer. Furthermore, the collection recess must provide sufficient space to collect the oxide layer so that the connection between the contact and the counter contact is sealed.

[0056] First, the contact surface 110 will be described in general terms in Fig. 2. As previously described with respect to Fig. 1, the conductors are moved towards each other in a contact direction in order to break through the oxide layers of the conductors. To control the movement and therefore the forces, the contact element 100 thus has a through opening 300, as shown in Fig. 2. The through opening 300 passes through the contact surface 110 and the opposite contact surface such that a screw can pass through the through opening 300.

[0057] Thus, the through openings 300 allow for the insertion of fastening means, such as screws, to connect the conductors. When the screws are tightened, the conductors move towards each other and the contact protrusions can break through the oxide layer.

[0058] It should be noted that the contact elements do not necessarily require through openings to allow the conductors to be moved towards each other: for example, a screw clamp may be used to move the conductors towards each other.

[0059] The through opening 300 is advantageous due to easier handling of the conductors 1000, 1000' and lower space requirements. For example, the diameter of the screw may be defined by the diameter DD of the through opening 300. A diameter DD of 0.5 cm or more and / or 1.5 cm or less has been found to be advantageous, so as to be able to use commercially available screws of sizes M5 to M15.

[0060] Furthermore, the area of ​​the structured contact surface 110 can be simply defined by the through opening 300, i.e. as a ring with a width dR around the through opening 300. Advantageously, the ring has a width dR of 0.2 cm or more and / or 5 cm or less. Such a ring-shaped contact surface 110 allows a symmetrical transmission of forces to the fastening means. As mentioned above, a narrow ring allows a slight increase in the force per surface area. On the other hand, a wide ring allows a larger effective contact surface.

[0061] The structure of the contact surface 110 is shown in Figures 3 to 5. The contact elements, without the structure, are shown in Figure 2 only for illustrative purposes.

[0062] Figures 3 and 4 are top views of structures corresponding to two examples. Figure 3 shows a contact pin 107 and Figure 4 shows contact blades 108_1, 108_2. Figure 5 is a cross-sectional view along line VV in Figures 3 and 4. The two examples may be the same in the cross-sectional view of Figure 5, and both examples will be described with reference to Figure 5.

[0063] In the example shown in Fig. 5, the two contact surfaces 110, 110' have the same design. This is a particularly cost-effective and efficient solution, since only the contact element 100 has to be structured and coated. However, to achieve the effects described in this description, it is sufficient for only one of the contact surfaces to have the structure described below. Alternatively or additionally, for example, one of the conductors may have the structure described.

[0064] As shown in FIG. 5, each contact bump 106 is described by the ratio of the width b of the base 103 of the contact bump 104 (shown as a dotted line between the base body 102 and the contact bump 104 ) to the height h of the contact bump 104 .

[0065] As previously mentioned, as the width b and effective contact area increase, the stability of the structure increases. At the same time, as the width b increases, the space available for absorbing oxide decreases, the perimeter of the contact that must be sealed increases, and the surface forces decrease.

[0066] As previously mentioned, as the height increases, the space for the oxide layer becomes larger and the stability of the contact protrusion decreases. Based on these considerations, the optimum ratio of width b to height h is 2 to 10. As previously mentioned, this ratio may be advantageously 3 to 8, and more advantageously 4 to 7. As previously mentioned, the lower limit is determined by other effects than the upper limit, so any combination of smaller and larger values ​​is possible.

[0067] A width b is typically defined, the width b being defined perpendicular to the contact direction 200. It is preferred that the width is greater than 0.25 mm and / or less than or equal to 1.5 mm. This results in the height of the contact bump.

[0068] If the structure is embossed, the width b is defined by the embossing die. Figures 6 to 16 show different types of embossing dies. For example, the dies of Figures 6 and 12 form structures with a base width of 0.5 mm. Alternatively, the die of Figure 9 forms structures with a base width of 1.0 mm. Alternatively, the angular dimensions can be used to define the structures, as shown in Figure 16.

[0069] Alternatively, for example, the structure can be etched, in which case the width b is defined by a mask. The width b may also be defined for other structuring processes.

[0070] Furthermore, the structuring process results in the shape of the collection recess 120, which serves to receive the oxide. The collection recess 120, which is arranged between two adjacent contact protrusions 104, has a cross section in the shape of a triangle with sides 122, 124, the angle of the collection recess between the surface normal of the contact surface and the edge of the collection recess being equal to or less than 45°, preferably less than 30°, most preferably less than 10°, in particular the structure being formed by embossing.

[0071] A corresponding height h of the contact bump is obtained by the structuring process. As shown in Fig. 5, the height h is defined here in the contact direction 200. If the height h is defined instead of the width b, it is preferred that the height h is selected such that the height h of the contact bump is greater than or equal to 0.01 mm and / or the height h of the contact bump is less than or equal to 1 mm. This means that the width b of the contact bump is also due to the height h.

[0072] Preferably, after structuring a nickel layer is applied, which is not shown in figure 5. The nickel layer has a thickness of 0.1 μm or more and / or the nickel layer has a thickness of 10 μm or less.

[0073] The thickness of the base body DG, which is preferably greater than or equal to 1 mm and / or less than or equal to 5 mm, is also measured in the contact direction 200. The thickness is usually measured before the structuring process.

[0074] As mentioned before, there are adjacent contact protrusions 104 having contact bases 103'. The distance between two closely adjacent contact protrusions 104 is essentially equal to size B. This distance then also defines the distance between closely adjacent contact points 106, where a contact point is defined as the centroid of the contact protrusions of the contact surface. This distance is preferably greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm.

[0075] In addition, a gap 130 is also formed between two adjacent contact protrusions 104, as shown in Fig. 5. The gap can be formed by cylindrical punch protrusions 2132 disposed between pyramidal punch protrusions 2134, as shown in detail X of Fig. 7.

[0076] The function of the gap 130, for example as shown in Fig. 5, is explained by way of example with reference to Fig. 3. In the example of Fig. 3, the contact element comprises at least three adjacent contact pins, where a first distance A1 between a first contact 106_M of a central contact pin and a first adjacent contact 106_1 of a first adjacent contact pin is not equal to a second distance A2 between the central contact 106_M and a second adjacent contact 106_2 of a second adjacent contact pin. This allows an asymmetric arrangement of the contacts, which is advantageous when the contact element is used for repeated contact of conductors. In this case, the contacts 106_1, 106_2, 106_M are the surface centers of the contact protrusions of the contact surface.

[0077] It is particularly advantageous if adjacent contact pins are arranged on a radius connecting the through opening and the edge of the connection lock, an example of such an arrangement is shown by the line AA in figures 6 and 9.

[0078] Instead of a gap, an asymmetric arrangement can be realized by structuring, as shown in FIG. 4. The contact element comprises two adjacent contact blades 108_1, 108_2. A bend 109 prevents the contact blades from forming a radius starting from the through opening. A punch for forming the structure is shown, for example, in FIG. 15. Alternatively, the contact blades do not form a circular line around the through opening. A punch for forming this structure is shown, for example, in FIG. 12, whereby an elliptical contact blade is formed. Here, the distance between the centroids of the opposing points is the periodic distance between two adjacent consecutive blades.

[0079] The material of the base body 102 and the protrusions 104 includes aluminum and / or copper.

[0080] The method for manufacturing a current-carrying contact element particularly comprises the following steps.

[0081] One step is structuring the base body 130 to form a structured contact surface, the structured contact surface having a number of collection recesses for receiving oxide and a number of contact protrusions for contacting conductors, the structuring can be performed by machining or a forming process.

[0082] The method then includes the step of coating the embossed contact surface with nickel to form a nickel layer that hardens the contact protrusions such that the coated contact protrusions destroy the oxide layer of the conductor they contact upon connection with the conductor.

[0083] In the method, a ratio of a width b of the base of the contact projection to a height h of the contact projection is 2-10.

[0084] The method may further include structuring the structured contact surface of the base body to form a collection recess having a triangular cross section perpendicular to the contact surface, the angle of the collection recess between a surface normal of the contact surface and an edge of the collection recess being less than or equal to 45°, preferably less than 30°, and most preferably less than 10°.

[0085] This can be achieved, for example, by forming collection recesses by embossing or machining.

[0086] Although a base body having two structured surfaces is shown in FIG. 1 above, a base body having only one structured base surface 110 or 110' can also enable the aforementioned effects.

[0087] This specification is based on the discovery that nickel has the particularly advantageous properties mentioned above. It remains to be seen whether other materials such as Au, AgPd, Cr, W, and W compounds such as WC, Ag-WC, Ni-WC, or other metals also have these advantageous properties, i.e., that such metals have properties superior to known Ag, Cu, or Al coatings. If this becomes evident, the term nickel layer can be replaced in the above description with metal layer, whereby the metal layer includes at least one of the metals Au, AgPd, Cr, and W. [Explanation of symbols]

[0088] 10 Connected Systems 100 contact elements 102 Base body 103 Base 103' Base point 104 Contact protrusion 106, 106_1, 106_2, 106_M contacts 107 Contact pin 108_1, 108_2 Contact blade 110, 110' contact surface 120 Collection recess 122, 124 sides 130 Gap 200 Contact direction 300 Through opening 1000, 1000' conductor, busbar 1100 Oxide layer 2132 Highlighting of cylindrical stamping die 2134 Highlighting of pyramidal shaped stamping

Claims

1. A current-carrying contact element (100) having at least one contact surface (110, 110') for electrically contacting two opposing electrical conductors (1000, 1000') in a contact direction (200), The contact element (100) comprises: - a base body (102) having a structured contact surface (110), said structured contact surface (110) having a number of collection recesses (120) for receiving oxides between a number of contact projections (104) projecting in said contact direction (200), each contact projection (104) having a contact (106) for contacting said conductor (1000) at said contact (106); a nickel layer applied to the structured contact surface (110), the nickel layer being intended to harden the contact bumps (104) so ​​that the coated contact bumps (104), when connected to the conductor (1000), break the oxide layer (1100) of the conductor (1000) they contact, exposing the bare counter contacts, the nickel layer being intended to seal the contacts (106) and the bare counter contacts against oxygen; Equipped with the ratio of the width (b) of the base (103) of the contact protrusion (104) to the height (h) of the contact protrusion (104) is 2 or more and 10 or less; Contact element.

2. said base body (102) has a through opening (300) connecting said two contact surfaces (110, 110'); said through opening (300) for passing fastening means for connecting said conductors (1000, 1000'), in particular said through opening (300) having a diameter (DD) of 0.5 cm or more and / or 1.5 cm or less; The contact element (100) of claim 1.

3. The distance (A1) between two adjacent contacts (106) is 0.5 mm or more and / or 1.5 mm or less; A contact element (100) according to claim 1 or 2.

4. At least three adjacent contact pins (107); To allow for an asymmetric arrangement of the contacts, a first distance (A1) between a first contact (106_M) of a central contact pin (107) and a first adjacent contact (106_1) of a first adjacent contact pin (107) is not equal to a second distance (A2) between the central contact (106_M) and a second adjacent contact (106_2) of a second adjacent contact pin (107); A contact element (100) according to any one of claims 1 to 3.

5. the adjacent contact pins (107) are arranged on a radius connecting the through opening (300) and the edge of the contact element, in particular the first distance being 0.5 mm or more and / or 1.5 mm or less and / or the second distance being 1.5 times the first distance or more, A contact element (100) according to claim 2 or 4.

6. Two adjacent contact blades (108), In order to allow an asymmetric arrangement of the contacts, the contact blades (108) do not form a circular line around the through opening (300) and do not form a radius starting from the through opening (300), in particular the distance between two adjacent contacts (106) is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm, The contact element (100) of claim 2.

7. the structured contact surface around the through opening (300) is a ring having a width (dR) of 0.2 cm or more and / or 5 cm or less; A contact element (100) according to any one of claims 2 to 6.

8. the material of the base body (102) comprises aluminum and / or copper; The base body (102) has a thickness of 1 mm or more, and / or the base body (102) has a thickness (DG) of 5 mm or less. A contact element (100) according to any one of the preceding claims.

9. The height (h) of the contact protrusion (104) is 0.01 mm or more, and the height (h) of the contact protrusion (102) is 1 mm or less; The nickel layer has a thickness of 0.1 μm or more, and / or the nickel layer has a thickness of 10 μm or less. A contact element (100) according to any one of the preceding claims.

10. A current carrying contact element (100) according to any one of claims 1 to 9 and two opposing electrical conductors (1000, 1000'), the conductor (1000) contacting the structured contact surface (110) of the contact element (100) comprises aluminum; An electrical connection system (10).

11. Further comprising a screw for mechanically connecting said electrical conductors (1000, 1000'). The electrical connection system (10) of claim 10.

12. At least one of the electrical conductors (1000, 1000') is a busbar; An electrical connection system (10) according to claim 10 or 11.

13. A method for manufacturing a current-carrying contact element (100) according to any one of claims 1 to 9, comprising the steps of: The method comprises: - structuring the base body (102) to form a structured contact surface (110), said structured contact surface (110) having a number of collection recesses (120) for receiving oxide and a number of contact protrusions (104) for contacting said conductor (1000); - coating said structured contact surface (110) with nickel to form a nickel layer, said nickel layer being intended to harden said contact bumps (104) so ​​that said coated contact bumps (104) destroy the oxide layer (1100) of said conductor (1000) that they contact when connected to said conductor (1000); Including, the ratio of the width (b) of the base (103) of the contact protrusion (104) to the height (h) of the contact protrusion (104) is 2 or more and 10 or less; method.

14. the structured contact surface (110) of the base body is structured to form a triangular collection recess (120) in cross section perpendicular to the contact surface, the angle (α / 2) of the collection recess between the surface normal of the contact surface and the edge of the collection recess being equal to or smaller than 30°, preferably smaller than 10°; The method of claim 13.

15. The structure of the collection recess (120) is formed by embossing.

15. The method according to claim 13 or 14.

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