Current-carrying contact element having structured contact surface

Abstract

The invention relates to a current-carrying contact element (100) having at least one contact surface for electrically contacting two opposite electrical conductors in a contact direction (200). The contact element comprises a base body (102) having a structured contact surface (110), the structured contact surface (110) having a plurality of collecting recesses (120) for receiving oxides between a plurality of contact protrusions (104) protruding in the contact direction (200), each contact protrusion having a contact point for contacting a conductor at the contact point; a nickel layer applied to the structured contact surface, the nickel layer for hardening the contact protrusions such that the coated contact protrusions destroy the oxide layer on the conductor to be contacted when connected to the conductor to expose the exposed mating contact point, and the nickel layer for sealing the contact point (106) and the exposed mating contact point from oxygen; and wherein the ratio of the width at the base (103) of the contact protrusion to the height of the contact protrusion is greater than or equal to 2 and less than or equal to 10.

Description

Technical Field

[0001] The subject matter described herein generally relates to current-carrying contact elements having at least one structured contact surface and methods of making such current-carrying contact elements. Background Art

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

[0003] In the past, intermetallic phases between aluminum and silver and between aluminum and copper were investigated as the main cause of failures in non-bonded, current-carrying connections with the corresponding material combinations. However, the observed resistance increase could not be fully explained by the grown phases.

[0004] In particular, the contact resistance increases due to oxidation. If the conductor (e.g. Fig.17 If a bus bar 1000 as shown is connected, the surface must be treated before each new contacting process in order to remove the oxide layer 1100. For example, a wire brush is used to remove the oxide layer from the surface of aluminum or copper. Summary of the invention

[0005] Therefore, the task is to solve the above problems. In particular, the task is to reduce the effort required for contacting. Time-consuming and expensive preparation measures should be minimized. Another task is to ensure that the contact is stable over long periods of time. Another task is to ensure that the quality of the contact remains consistent with repeated contacting.

[0006] The above-mentioned object is achieved by the subject matter of the independent patent claims. Advantageous further embodiments are the subject matter of the dependent patent claims.

[0007] According to a general aspect, a current-carrying contact element solves the above-mentioned problems. The contact element has a contact protrusion with a nickel layer, which can destroy the oxide layer on the conductor to be contacted to form a metal contact point, because nickel is harder than the aluminum of the conductor. The hard nickel associated with the soft aluminum (which is located below the oxide layer) causes the softer aluminum to flow, and this flow destroys the oxide. This results in good contact (contact resistance less than 5μΩ). In addition, the nickel layer enables long-term stability because the nickel can surprisingly seal the exposed mating contact to prevent oxygen, so that no new oxide layer can grow. With the special size of the contact protrusion, the conditions of low connection resistance and high long-term stability can be achieved, because the contact protrusion withstands the contact pressure, especially when the opposite conductors are pressed together, and meets 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 opposing contact surfaces, for electrically contacting two opposing electrical conductors in a contact direction. The two conductors are moved together, i.e. towards each other in the contact direction, so that the contact element is subjected to a compressive force in the contact direction. For example, the conductors can be moved together by a screw or a clamp. In other words, the pressure is applied perpendicular to the contact surface of the contact element. The contact element can also be formed as one piece with one of the conductors. In other words, the contact surface of the contact element is in contact with the conductor. In other words, the conductor comprises the contact element at one end.

[0009] Current-carrying contact elements may also be referred to as current-carrying contact fixing elements. Contact elements must be distinguished from screw locks, which are intended to prevent unintentional loosening or loosening of a screw connection, since the screw lock is placed between the screw head and the element to be contacted. Similar to screw locks, contact elements are intended to prevent unintentional degradation of the connection. In addition to the property of fixing long-term contacts, as described below, contact elements enable the electrical connection properties to be optimized and the preparatory steps to be minimized.

[0010] In particular, the contact element comprises or consists of a substrate having at least one structured contact surface. The two opposing contact surfaces can also be structured. In this case, a structured contact surface is understood to be a surface that has been processed by a processing technique such as embossing, etching, milling, etc., in order to produce a structure with a defined shape. Advantageously, both opposing contact surfaces of the substrate are structured.

[0011] The defining shape of the structured contact surface is a plurality of collecting recesses between a plurality of contact protrusions protruding in the contact direction. The collecting recesses can be formed, for example, by pressing the contact surface. This enables a cost-effective process to produce the recesses and protrusions, since only one process step is required for structuring and the stamp (also called punch) can be reused. Alternatively, of course, ablation processes can also be used, which can achieve higher precision than embossing, but are generally also more expensive, since, for example, masking steps and etching steps are required.

[0012] The structure enables the oxide removed from the conductor to be contacted to be absorbed in the recesses and enables a contact point to be provided at each contact protrusion in order to contact the conductor at the contact point. The structure is thus optimized for two tasks, namely that the contact point is as large as possible on the surface in order to minimize the contact resistance. Furthermore, the recesses are designed so that they provide enough space to completely absorb the removed oxide. Therefore, the recesses are usually deeper than they are wide.

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

[0014] For example, if the manufacturing process is an etching process, the recess can be a groove, i.e., an approximately rectangular shape in a cross section perpendicular to the contact surface, whereby the aspect ratio of the width to the depth of the rectangle is greater than or equal to 0.05 and less than or equal to 0.15. When milling, any shape having a perimeter shape forming a polygon can be produced.

[0015] In addition, the contact element includes a nickel layer applied to the structured contact surface. For example, the nickel layer can be applied using an electroplating process. Here, a substrate made of a material with high conductivity such as aluminum or copper is plated with nickel to achieve the two effects described below. It should be noted that a body made entirely of nickel achieves the same effect, but has a lower conductivity, so the connection resistance is greater than the case where only the nickel layer is applied to a body made of copper. The nickel layer is defined herein as a layer containing nickel. For example, the nickel layer can consist only of nickel. However, the nickel layer can also contain nickel compounds, such as NiP, etc. The mass fraction of nickel in the layer is preferably greater than or equal to 50%. Particularly preferably, it is greater than or equal to 75%. Even more preferably, it is greater than or equal to 90%.

[0016] The nickel layer is capable of hardening the contact protrusions so that the coated contact protrusions, when connected to the conductors, break through the oxide layer on the conductors to be contacted to expose the bare mating contact points, which are usually made of a more conductive material such as aluminum or copper. Thus, the nickel layer allows the preparation steps to be minimized, since there is no need to clean the surface of the conductors to be contacted and expose the mating contact points in the joining step.

[0017] The nickel layer also enables the contact points and the exposed mating contacts to be microscopically sealed from oxygen. Surprisingly, nickel has better properties than silver, for example. This surprisingly tight contact point formation enables the connection to remain stable over a longer period of time.

[0018] Since nickel has significantly higher melting and recrystallization temperatures compared to silver and tin, there is no adhesion between the contact element and the mating contact when the connection is released. Due to the higher operating temperatures, as expected with tin- and silver-plated surfaces, cold welding can cause the coating of the contact element to become damaged when loosened, which impairs reassembly.

[0019] The contact projections can form lug-shaped (hereinafter also referred to as rod-shaped) contact pins protruding in the contact direction. The term pin is used here to describe an elongated object with a predominantly constant, for example circular, square or polygonal cross section. In this case, the size of the cross section is greater than its length. Alternatively, the contact projections can form lamellar contact sheets protruding in the contact direction. Lamella is a term used for ribs that are repeated within a structure that always has the same form, i.e. it is a periodic structure.

[0020] The base of the contact protrusion is defined here as the deepest point of the structure. For example, this is the depth of embossing, etching, milling, etc. The width of the contact pin is the diagonal. In the case of a circular cross section, this would be the diameter. The width of the contact patch is the distance between two opposite sides of the patch 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. When embossing, the width of the contact protrusion results from the width of the pattern in the embossing mold, which structures the contact protrusion, because the embossing takes place in the contact direction.

[0021] The height is equal to the depth of the resulting structure. As mentioned above, this dimension depends on the width of the contact protrusion and is achieved by the chosen process. For example, this is defined by the force with which the imprinting mold is applied, how long the etching takes, or how hard the contact element is.

[0022] It has been found that the ratio of the width at the base of the contact protrusion to 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 collapses first, and the contact protrusion is stable. It has also been found that the ratio of the width at the base of the contact protrusion to the height of the contact protrusion must be less than or equal to 10 in order to transmit sufficient force to the oxide layer to rupture it. In the case of larger ratios, not enough force will be transmitted in the contact point, the oxide layer cannot be absorbed in the collecting recess, but will remain in the contact position, and / or the contact point cannot be sealed due to the remaining oxide layer.

[0023] According to a preferred example, the ratio of the width at the base of the contact protrusion to the height of the contact protrusion is greater than or equal to 3. It is particularly preferred that the ratio is greater than or equal to 4.

[0024] According to another preferred example, the ratio of the width at the base of the contact protrusion to the height of the contact protrusion is less than or equal to 8. This ratio is particularly preferably less than or equal to 6.

[0025] According to a second aspect, in addition to the first aspect, the substrate has a through opening connecting the two contact surfaces. The through opening is preferably formed before structuring. The through opening enables a fastening device (such as a screw) to pass through the contact element. This allows the conductors to be pressed together with a predetermined force, which can be defined by the fastening device. This allows the contact protrusion to transmit enough force to destroy the oxide layer on the conductor, the contact protrusion is not deformed, the contact element is allowed to be reused, and the nickel layer seals the mating contact point, allowing long-term contact. The through opening is first formed and then the through opening is structured. Since the surface area that must be deformed during stamping is smaller, the surface pressure can be increased with the same force, so that a better structure can be achieved.

[0026] Advantageously, the through opening has a diameter greater than or equal to 0.5 cm and / or less than or equal to 1.5 cm. This 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 contact points is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm. A smaller distance increases the number of recesses to accommodate oxides. The greater the distance, the fewer contact points need to be sealed. Preferably, the distance between two adjacent contact points is greater than or equal to 0.75 mm and / or less than or equal to 1.25 mm.

[0028] According to a fourth aspect, in addition to any of the above aspects, the plurality of contact protrusions include at least three adjacent contact pins, wherein a first distance between a first contact point on a center contact pin and a first adjacent contact point on a first adjacent contact pin is not equal to a second distance between the center contact point and a second adjacent contact point on a second adjacent contact pin, so as to achieve an asymmetric arrangement of the contact points. This arrangement enables the oxide layer to be broken at a large number of new points on the conductor during re-contacting, during which the contact elements are usually slightly displaced, and thus this arrangement enables the oxide layer to be broken continuously.

[0029] According to a fifth aspect, in addition to the second and fourth aspects, adjacent contact pins are arranged on a radius connecting the through opening and the edge of the connecting fixture. The contact element rotates around the through opening, thus sufficiently destroying the axis of symmetry to ensure that the oxide layer is continuously destroyed during repeated connection. This simplifies the design of the mask (e.g., an imprint mold) and makes it possible to increase the number of contact protrusions per unit surface.

[0030] It is particularly preferred that the first distance is greater than or equal to 0.5 mm and less than or equal to 1.5 mm and / or the second distance is greater than or equal to 1.5 times the first distance.

[0031] According to the sixth aspect, in addition to the second aspect, the plurality of contact protrusions include at least two adjacent contact pieces, wherein the contact pieces do not form a circular line around the through opening and do not form a radius starting from the through opening to achieve an asymmetric arrangement of the contact points. This achieves the same effect as the fifth aspect. It is particularly preferred that the distance between two adjacent contact points on the contact piece is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm.

[0032] According to a seventh aspect, in addition to the second to sixth aspects, the structured contact surface surrounding the through opening is a ring with a width greater than or equal to 0.2 cm and / or less than or equal to 5 cm. The lower limit of the ring width is necessary to produce a sufficient contact surface. The upper limit helps to increase the contact force per unit surface area. A ring with a width greater than or equal to 1 cm and / or less than or equal to 2 cm is particularly preferred.

[0033] According to an eighth aspect, in addition to one of the above aspects, the material of the substrate comprises aluminum and / or copper. This enables the electrical conductivity in the substrate to be increased. For stability reasons, it is advantageous if the substrate has a thickness of at least greater than or equal to 1 mm. Additionally or alternatively, the thickness of the substrate may be less than or equal to 5 mm in order to achieve a compact design.

[0034] According to a ninth aspect, in addition to one of the above aspects, the height of the contact protrusion may be greater than or equal to 0.01 mm and / or the height of the contact protrusion may be less than or equal to 1 mm. A lower height of the contact protrusion may facilitate manufacturing. A greater height helps to accommodate a larger amount of oxide in the recess, thereby keeping the recess open even with repeated use. Particularly preferably, the height of the contact protrusion is greater than or equal to 0.05 mm and / or the height of the contact protrusion is less than or equal to 0.5 mm. Even more preferably, the height of the contact protrusion is greater than or equal to 0.075 mm and / or the height of the contact protrusion is less than or equal to 0.25 mm.

[0035] Additionally or alternatively, the nickel layer may have a thickness greater than or equal to 0.1 μm and / or the nickel layer may have a thickness less than or equal to 10 μm.

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

[0037] The eleventh aspect relates to the electrical connection system according to the tenth aspect, further comprising a screw for mechanically connecting the electrical conductors. As described above, the screw is capable of force transmission to destroy the oxide layer.

[0038] A twelfth aspect relates to the electrical connection system according to the tenth or eleventh aspect, wherein at least one of the electrical conductors is a bus bar. Thus, the system can be particularly useful for high current applications, such as electromobility.

[0039] A thirteenth aspect relates to a method of manufacturing a current-carrying contact element according to any of the above aspects, the method comprising the following steps:

[0040] structuring the substrate to form a structured contact surface having a plurality of collecting recesses for receiving oxide and a plurality of contact protrusions for contacting the conductor;

[0041] coating the structured, in particular embossed, contact surface with nickel to form a nickel layer, which serves to harden the contact bumps so that the coated contact bumps, when connected to the conductor, destroy an oxide layer on the conductor to be contacted; and

[0042] The ratio of the width (b) at the base of the contact protrusion to the height (h) of the contact protrusion is greater than or equal to 2 and less than or equal to 10.

[0043] For further details, reference is made to the above description of aspects one to twelve.

[0044] The fourteenth aspect relates to a method according to the thirteenth aspect, wherein the structured contact surface of the structured substrate is so as to produce a collecting recess in a cross section perpendicular to the contact surface, wherein the angle between the surface normal of the contact surface in the collecting recess and the edge of the capture recess is less than or equal to 45°, preferably less than 30°, and most preferably less than 10°, in particular, wherein the structure is produced by embossing.

[0045] As mentioned above, the collecting recess has an approximately triangular shape at the lowest point (hereinafter also referred to as the base). The side faces of the collecting recess and the normal to the contact surface form a triangle. The small angle allows the contact surface to be maximized, which results in lower line resistance.

[0046] A fifteenth aspect relates to a method according to the thirteenth or fourteenth aspect, wherein the collecting recess is realized by an embossing process. This is particularly cost-effective.

[0047] Alternatively, a recess may be etched. As described above, the etched depression generally forms a groove. Such a groove may be similarly described as a triangle of the fourteenth aspect, i.e. by connecting to the deepest point of the side.

[0048] Furthermore, a through-opening can be formed in the base body before embossing. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to better understand the present invention, the present invention is explained in more detail using the embodiments shown in the following drawings. The same components have the same reference numerals and the same component names. In addition, some features or combinations of features from the different embodiments shown and described may represent independent inventive solutions or solutions according to the present invention.

[0050] The accompanying drawings show:

[0051] Figure 1 It is a connection system based on one aspect;

[0052] Figure 2 is a top view of a connection element according to one aspect;

[0053] Figure 3 is the first example Figure 2 Details of the connecting elements III;

[0054] Figure 4 is the corresponding second example Figure 2 Details of the connecting elements III;

[0055] Figure 5 It is along Figure 3 or Figure 4 A cross-sectional view of the cross-sectional axis VV;

[0056] Figure 6 is an embossing mold for producing a structured surface of a connecting element according to a first example;

[0057] Figure 7 yes Figure 6 Details of the stamping die U;

[0058] Figure 8 is along Figure 6 A cross-sectional view of the cross-sectional axis AA;

[0059] Fig. 9 is an embossing mold for producing a structured surface of a connecting element according to a variation of the first example;

[0060] Fig.10 yes Fig. 9 Details of the stamping die X;

[0061] Fig.11 is along Fig. 9 A cross-sectional view of the cross-sectional axis AA;

[0062] Fig.12 is an embossing mold for producing a structured surface of a connecting element according to a second example;

[0063] Fig.13 yes Fig.12 Details of the stamping die V;

[0064] Fig.14 is along Fig.12 A cross-sectional view of the cross-sectional axis AA;

[0065] Fig.15 is an embossing mold for producing a structured surface of a connecting element according to a variation of the second example;

[0066] Fig.16 yes Fig.15 Details of the stamping die W; and

[0067] Fig.17 is a connection system according to the prior art. DETAILED DESCRIPTION

[0068] The contact element will now be described with reference to the drawings. Figure 1 An electrical connection system having conductors 1000, 1000' is shown. Fig.17 The system 10 is connected in a similar manner in the contact direction. Furthermore, the system 10 comprises a current-carrying contact element 100 .

[0069] like Figure 1 As shown, the current-carrying contact element 100 has two opposite contact surfaces 110, 110'. One contact surface 110, 110' is used to make electrical contact with the opposite electrical conductor 1000, 1000'. The contact is made when the opposite electrical conductors 1000, 1000' move toward each other in the contact direction 200. Figure 1 As shown, the contact direction 200 is perpendicular to the surfaces of the two opposing contact surfaces 110 , 110 ′.

[0070] like Figure 1 As further shown in FIG. 1 , the contact element 100 has a base body 102 with a structured contact surface 110, 110'. In particular, a plurality of contact protrusions 104 protrude from the base body 102 in a contact direction 200. Each contact protrusion 104 has a contact point 106 for contacting the conductor 1000 at the contact point 106. The contact point 106 is here to be understood as a point or surface on the contact element 100 that is electrically connected to a mating contact point (not shown) formed on the conductor 1000, 1000'. Electrical connection means that when the contact element 100 is connected to at least one of the conductors 1000, 1000', an electric current can be conducted through the connection at the contact point and the mating contact point.

[0071] Furthermore, the structured contact surface 110 , 110 ′ has a plurality of collecting recesses 120 which do not contribute significantly to the current flow. The collecting recesses 120 serve to collect at least parts of the oxide layer 1100 .

[0072] Furthermore, a nickel layer (not shown) is applied to the structured contact surface 110, 110'. The nickel layer serves to harden the contact protrusions 104 so that the coated contact protrusions 104, when connected to the conductor 100, break through the oxide layer 1100 on the conductor 1000 to be contacted, in order to expose bare mating contacts not shown.

[0073] If the two conductors 1000, 1000' are now moved toward each other in the contact direction 200, the contact protrusion 104 breaks through the oxide layer 1100. As a result, the electrical resistance between the conductor 1000, 1000' and the contact element 100 is reduced, since the electrical contact is not made via the insulating oxide layer 1100, but the contact point 106 is in direct contact with the exposed mating contact point of the conductor 1000, 1000'.

[0074] Surprisingly, it was found that the nickel layer enables the contact point 106 and the exposed mating contact point to be sealed against oxygen for a long time, making the connection stable over the long term. Previously, nickel was expected to be inferior to more expensive metals (such as silver). Therefore, the long time is defined relative to an equivalent contact made by silver.

[0075] In order to utilize the above-mentioned effect, the contact protrusion 104 is designed as follows Figures 2 to 5 As shown. Basic considerations for the structuring of the contact element are, for example, that the effective contact surface, i.e. the sum of the surfaces of the contact points, is as large as possible. In addition, the contact points must transmit sufficient force per unit surface area to penetrate the oxide layer. Furthermore, the collecting recesses must provide sufficient space to capture the oxide layer so that the connection between the contact part and the mating contact part is sealed.

[0076] First, in Figure 2 The contact surface 110 is generally described in Figure 1 As described, the conductors are moved towards each other in the contact direction in order to break through the oxide layer on the conductors. In order to control the movement and thus the force, the contact element 100 therefore has a through opening 300, such as Figure 2 The through opening 300 extends through the contact surface 110 and the opposing contact surface so that the screw can pass through the through opening 300 .

[0077] Thus, the through opening 300 allows the insertion of a fastening means, such as a screw, to connect the conductors. When the screw is tightened, the conductors move towards each other and the contact protrusions can break through the oxide layer.

[0078] It should be noted that the contact element does not necessarily need a through opening so that the conductors can be moved towards each other. For example, a screw clamp can also be used to move the conductors towards each other.

[0079] The through opening 300 is advantageous because the handling of the conductor 1000, 1000' is simplified and the space requirement is reduced. For example, the screw diameter can be specified by the diameter DD of the through opening 300. It has been found that a diameter DD greater than or equal to 0.5 cm and / or less than or equal to 1.5 cm is advantageous, so that commercially available screws of size M5 to M15 can be used.

[0080] Furthermore, the area of ​​the structured contact surface 110 can be defined in a simple manner by the through opening 300, namely as a ring with a width dR around the through opening 300. It is advantageous if the ring has a width dR greater than or equal to 0.2 cm and / or less than or equal to 5 cm. Such an annular contact surface 110 enables a symmetrical transmission of forces to the fastening means. As mentioned above, a narrow ring can slightly increase the force per unit surface area. On the other hand, a wide ring enables a larger effective contact surface.

[0081] The structure of the contact surface 110 is Figures 3 to 5 For illustrative reasons, the contact elements without structure are shown only in Figure 2 Shown in.

[0082] Figure 3 and Figure 4 are top views of the structures corresponding to the two examples. Figure 3 A contact pin 107 is shown, Figure 4 Contact strips 108_1 , 108_2 are shown. Figure 5 is along Figure 3 and Figure 4 The two examples are shown in Figure 2. Figure 5 The cross-sectional views may be the same and refer to Figure 5 Describe these two examples.

[0083] exist Figure 5 In the example shown, 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 needs to be structured and coated. However, in order to achieve the effects discussed in this specification, 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 can also have the described structure.

[0084] like Figure 5As shown, each contact protrusion 106 is described by the ratio of a width b at the base 103 of the contact protrusion 104 , represented by a dashed line between the base 102 and the contact protrusion 104 , to a height h of the contact protrusion 104 .

[0085] As mentioned above, the stability of the structure increases with the width b, and the effective contact surface increases. At the same time, as the width b increases, the space available for absorbing oxides decreases, the circumference of the contact point that needs to be sealed increases, and the surface force decreases.

[0086] As described above, as the height increases, the space for the oxide layer increases, and the stability of the contact protrusion decreases. Based on these considerations, the optimal ratio of width b to height h is greater than or equal to 2 and less than or equal to 10. As described above, the ratio can be advantageously greater than or equal to 3 and less than or equal to 8, and even more advantageously greater than or equal to 4 and less than or equal to 7. Any combination of lower and upper limit values ​​is possible, because, as described above, the lower limit is determined by other influences in addition to the upper limit.

[0087] Typically a width b is specified, whereby the width b is defined perpendicular to the contact direction 200. Preferably, the width is greater than 0.25 mm and / or less than or equal to 1.5 mm. This results in a height h of the contact protrusion.

[0088] If the structure is embossed, the width b is defined by the embossing stamp. Figures 6 to 16 Different types of stamping dies are shown. For example, Figure 6 and Fig.12 The stamp in produces a structure with a base width of 0.5 mm. Alternatively, Fig. 9 The stamp in produces a structure with a base width of 1.0 mm. Alternatively, the structure can also be defined using angular dimensions, such as Fig.16 shown.

[0089] Alternatively, for example, the structure can be etched. The width b is then defined by the mask. The same can be defined for other structuring processes.

[0090] Furthermore, the structuring process results in the shape of a collecting recess 120 for receiving oxide. A collecting recess 120 arranged between two adjacent and abutting contact protrusions 104 has in cross section a triangular shape with legs 122, 124, wherein the angle between the surface normal of the contact surface in the collecting recess and the edge of the collecting recess is less than or equal to 45°, preferably less than 30°, most preferably less than 10°, in particular wherein the structure is produced by embossing.

[0091] The corresponding height h of the contact protrusion is obtained by the structuring process. Figure 5As shown, the height h is defined here in the contact direction 200. If the height h is to be defined instead of the width b, the height h is preferably selected such that the height h of the contact protrusion is greater than or equal to 0.01 mm and / or the height h of the contact protrusion is less than or equal to 1 mm. This means that the width b of the contact protrusion is also caused by the height h.

[0092] Figure 5 The nickel layer is not shown in the figure, which is preferably applied after the structuring. The nickel layer has a thickness greater than or equal to 0.1 μm and / or the nickel layer has a thickness less than or equal to 10 μm.

[0093] The thickness of the base body DG is also measured in the contact direction 200 and is preferably greater than or equal to 1 mm and / or less than or equal to 5 mm. The thickness is usually measured before the structuring process.

[0094] As described above, there are adjacent contact protrusions 104 with contact bases 103'. The distance between two adjacent contact protrusions 104 is substantially equal to dimension B. This distance then also defines the distance between adjacent, adjacent contact points 106. A contact point is defined here as the center of gravity of the contact protrusion in the contact surface. Preferably, this distance is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm.

[0095] In addition, if Figure 5 As shown, a gap 130 may also be formed between two adjacent contact protrusions 104. Figure 7 Detailed view of Figure X As shown, the gap can be created by the cylindrical stamping protrusions 2132 arranged between the pyramidal stamping protrusions 2134.

[0096] For example Figure 5 The function of the gap 130 shown in FIG. Figure 3 This is described by way of example. Figure 3 In the example of , the contact element comprises at least three adjacent contact pins, wherein a first distance A1 between a first contact point 106_M on an intermediate contact pin and a first adjacent contact point 106_1 on a first adjacent contact pin is not equal to a second distance A2 between the intermediate contact point 106_M and a second adjacent contact point 106_2 on a second adjacent contact pin. This enables an asymmetric arrangement of the contact points. This is advantageous if the contact element is used for repeated contacting of conductors. In this case, the contact points 106_1, 106_2, 106_M are the surface centers of the contact protrusions in the contact surface.

[0097] 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 given by Figure 6 and Fig. 9 The line AA in FIG.

[0098] As an alternative to gaps, an asymmetric arrangement can be achieved by structuring, e.g. Figure 4 As shown. The contact element includes two adjacent contact pieces 108_1 and 108_2. The curved portion 109 prevents the contact piece from forming a radius starting from the through opening. For example, Fig.15 . Alternatively, the contact blades do not form a circular line around the through opening. For example, in Fig.12 The punch used to produce this structure is shown in , whereby an elliptical contact patch is produced. Here, the distance between the centers of gravity of the counterpoints is the periodic distance between two adjacent consecutive patches.

[0099] The material of the base 102 and the protrusion 104 includes aluminum and / or copper.

[0100] The method for producing a current-carrying contact element comprises in particular the following steps.

[0101] One step is to structure the base body 130 to form a structured contact surface, wherein the structured contact surface has a plurality of collecting recesses for receiving oxides and a plurality of contact protrusions for contacting the conductors; the structuring can be performed by machining or by a forming process.

[0102] The method then comprises the step of coating the stamped contact surface with nickel to produce a nickel layer which hardens the contact protrusions so that the coated contact protrusions, when connected to the conductor, destroy the oxide layer on the conductor to be contacted.

[0103] In the method, a ratio of a width b at a base of the contact protrusion to a height h of the contact protrusion is greater than or equal to 2 and less than or equal to 10.

[0104] The method may also include structuring the contact surface of the structuring substrate to produce a collecting recess, the cross-section of which perpendicular to the contact surface is triangular, wherein the angle between the surface normal of the contact surface in the collecting recess and the edge of the collecting recess is less than or equal to 45°, preferably less than 30°, and most preferably less than 10°.

[0105] This can be achieved, for example, by embossing or machining to create the collecting recesses.

[0106] Even in the above Figure 1 , a substrate having two structured surfaces is shown; a substrate having only one structured base surface 110 or 110 ′ can also achieve the above-mentioned effect.

[0107] The present document is based on the discovery that nickel has the above-mentioned particularly advantageous properties. It is not known 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. these metals have better properties than the known Ag, Cu or Al coatings. If this becomes obvious, the term nickel layer can be replaced by the metal layer in the above description, wherein the metal layer includes at least one of the metals Au, AgPd, Cr and W.

[0108] Reference numerals list

[0109] Description of Reference Numerals

[0110] 10. Connecting the system

[0111] 100 Contact elements

[0112] 102 Matrix

[0113] 103 Base

[0114] 103' Base Point

[0115] 104 contact protrusion

[0116] 106, 106_1, 106_2, 106_M contact points

[0117] 107 contact pin

[0118] 108_1,108_2 contact piece

[0119] 110,110' contact surface

[0120] 120 collection recess

[0121] 122,124 Legs

[0122] 130 Gap

[0123] 200 Contact direction

[0124] 300 Through opening

[0125] 1000,1000' conductor, bus bar

[0126] 1100 Oxide layer

[0127] 2132 cylindrical stamping protrusion

[0128] 2134 Pyramid-shaped cylindrical stamping protrusions

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 current-carrying contact element (100) comprising: A substrate (102) having a structured contact surface (110), the structured contact surface (110) having a plurality of collecting recesses (120) for receiving oxides between a plurality of contact protrusions (104) protruding along the contact direction (200), each contact protrusion (104) having a contact point (106) for contacting the conductor (1000) at the contact point (106); a nickel layer applied to the structured contact surface (110), the nickel layer serving to harden the contact protrusions (104) so ​​that the coated contact protrusions (104) when connected to the conductor (1000) break the oxide layer (1100) on the conductor (1000) to be contacted to expose the bare mating contact point, and the nickel layer serving to seal the contact point (106) and the bare mating contact point from oxygen; and The ratio of the width (b) at the base (103) of the contact protrusion (104) to the height (h) of the contact protrusion (104) is greater than or equal to 2 and less than or equal to 10.

2. The contact element (100) according to claim 1, wherein: The base body (102) has a through opening (300) connecting the two contact surfaces (110, 110'), wherein the through opening (300) is used for passing a fastening device for connecting the conductor (1000, 1000'), in particular, The through opening (300) has a diameter (DD) greater than or equal to 0.5 cm and / or less than or equal to 1.5 cm.

3. The contact element (100) according to any one of the preceding claims, wherein: The distance (A1) between two adjacent contact points (106) is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm.

4. The contact element (100) according to any one of the preceding claims, comprising at least three adjacent contact pins (107), wherein: A first distance (A1) between a first contact point (106_M) on a middle contact pin (107) and a first adjacent contact point (106_1) on a first adjacent contact pin (107) is not equal to a second distance (A2) between the middle contact point (106_M) and a second adjacent contact point (106_2) on a second adjacent contact pin (107), so as to enable an asymmetric arrangement of the contact points.

5. The contact element (100) according to any one of claims 2 and 4, wherein: Adjacent contact pins (107) are arranged on a radius connecting the through opening (300) and the edge of the contact element, in particular, wherein the first distance is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm, and / or wherein the second distance is greater than or equal to 1.5 times the first distance.

6. The contact element (100) according to claim 2, comprising two adjacent contact strips (108), wherein: The contact strip (108) does not form a circular line around the through-opening (300) and does not form a radius starting from the through-opening (300) in order to enable an asymmetrical arrangement of the contact points, in particular wherein: The distance between two adjacent contact points (106) is greater than or equal to 0.5 mm and / or less than or equal to 1.5 mm.

7. The contact element (100) according to any one of claims 2 to 6, wherein: The structured contact surface surrounding the through opening (300) is a ring having a width (dR) greater than or equal to 0.2 cm and / or less than or equal to 5 cm.

8. The contact element (100) according to any one of the preceding claims, wherein The material of the substrate (102) includes aluminum and / or copper, the substrate (102) has a thickness greater than or equal to 1 mm and / or the substrate (102) has a thickness (DG) less than or equal to 5 mm.

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

10. An electrical connection system (10) comprising a current-carrying contact element (100) according to any of the preceding claims and two opposing electrical conductors (1000, 1000'), wherein the conductor (1000) contacting the structured contact surface (110) of the contact element (100) comprises aluminum.

11. The electrical connection system (10) according to claim 10, further comprising a screw for mechanically connecting the electrical conductors (1000, 1000').

12. The electrical connection system (10) according to any one of claims 10 and 11, wherein: At least one of the electrical conductors (1000, 1000') is a bus bar.

13. A method for manufacturing a current-carrying contact element (100) according to any one of the preceding claims, the method comprising the following steps: Structuring the substrate (102) to form a structured contact surface (110) having a plurality of collecting recesses (120) for receiving oxides and a plurality of contact protrusions (104) for contacting the conductor (1000); coating the structured contact surface (110) with nickel to form a nickel layer, the nickel layer being used to harden the contact protrusion (104) so ​​that the coated contact protrusion (104) breaks the oxide layer (1100) on the conductor (1000) to be contacted when connected to the conductor (1000); and The ratio of the width (b) at the base (103) of the contact protrusion (104) to the height (h) of the contact protrusion (104) is greater than or equal to 2 and less than or equal to 10.

14. The method according to claim 13, wherein: The structured contact surface (110) of the substrate is structured to produce a collecting recess (120), wherein a cross-section of the collecting recess (120) perpendicular to the contact surface is triangular, wherein an angle (α / 2) between a surface normal of the contact surface and an edge of the collecting recess in the collecting recess is less than or equal to 30°, preferably less than 10°.

15. The method according to claim 13 or 14, wherein: The structure of the collecting recess (120) is manufactured by embossing.

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