Connection arrangement and method for producing a connection arrangement

Abstract

Connection arrangement (100) comprising at least: - a metallic flat conductor (1) with a first through-opening (2), - a metallic contact element (3) with a through-opening (5) which is bonded to the flat conductor (1) in the area of ​​the first through-opening (2), - a connecting bolt (4) which extends at least partially through the through-opening (5) of the metallic contact element (3), characterized in that the through-opening (5) of the metallic contact element (3) has an excess size relative to the connecting bolt (4).

Description

[0001] The subject matter relates to a connection arrangement between a metallic flat part and a metallic contact element, as well as a method for manufacturing such a connection arrangement.

[0002] In electrical applications, particularly in automotive applications, flat conductors (so-called busbars) are increasingly used. These flat conductors are not only used as power lines, but also as battery cell connectors, module connectors, and similar applications. The flat conductors are generally formed from a flat metallic part. To connect contact elements, it is known to apply the contact elements to the surface of the flat metallic part and preferably join them there by a metallurgical bond, in particular by welding.

[0003] When welding a flat metal part made of one metallic material to a metallic contact element made of a second metallic material, increased contact corrosion can occur at the weld seam, depending on the material combination. Furthermore, when using aluminum or an aluminum alloy, especially for the flat part, the contact point can be damaged under high mechanical stress. When using aluminum or aluminum alloys, the metallic material can sag at the contact point.

[0004] Besides welding the flat part to the contact element, a mechanical fixing of the contact element to the flat part is also known. In this method, for example, a connecting bolt is pushed through a through-hole in the flat part, and the contact element is connected to the connecting bolt. The connecting bolt and / or the contact element are thus mechanically fixed to the flat part. This is usually done by screwing. Over time, and especially under mechanical stress, such a screw connection can become mechanically unstable, particularly when using aluminum or an aluminum alloy. Due to the contact pressure of the screw and mechanical stress, the material in the area of ​​the through-hole of the flat part can yield, resulting in plastic deformation of the flat part and causing the mechanical connection to loosen.In the worst-case scenario, the connection fails and the contact element detaches from the flat part. In the worst case, this leads to deteriorated electrical contact, resulting in increased resistance and consequently rising component temperatures, potentially even leading to a vehicle fire.

[0005] To prevent this, it has already been proposed to place a metallic contact element in the through-hole. This metallic contact element serves as a mechanical and electrical contact point for other connecting elements that are to be attached to the metallic flat part. For example, a sleeve-shaped contact element can be placed in the through-hole. A connecting bolt can then be inserted through this through-hole. The contact element thus stabilizes the mechanical connection between the flat part and the connecting bolt.

[0006] The dimensions and three-dimensional bending of the flat conductor must be adapted to its installation in the vehicle so that the electrical contact points within the vehicle are connected. However, manufacturing tolerances occur during the three-dimensional bending of flat conductors, both in terms of the spacing between the bends and in the bending angles and radii. This leads to tolerances between the contact points of the flat conductors and the vehicle's periphery. Tolerances also arise during vehicle assembly, both in the body-in-white and in the positioning of the connection components. Flat conductors with small cross-sections exhibit a certain degree of deformability, allowing them to be fitted into the vehicle's installation environment. With the increasing importance of high-voltage applications, flat conductors with larger cross-sections of 200 mm² and above are also gaining in significance.These flat cables are significantly stiffer and cannot easily be bent within the installation space. Therefore, a contact system is required that compensates for both the tolerances of the vehicle and the bends in the flat cables.

[0007] Accordingly, the task is to provide a connection arrangement that improves the compensation of manufacturing tolerances when the connection arrangement is assembled in a motor vehicle.

[0008] This problem is solved by a connection arrangement according to claim 1.

[0009] This document proposes a metallic flat conductor with at least one contact element. The metallic flat conductor can have a polygonal, particularly quadrilateral, cross-sectional profile. Specifically, it can have a square or rectangular cross-sectional profile, with rounded edges. The cross-sectional profile of the flat conductor can consist of two parallel wide sides and two parallel narrow sides, which may optionally have rounded edges. A wide surface of the flat conductor extends longitudinally along the wide sides, and a narrow surface extends longitudinally along the short sides. The flat conductor has a through-hole, which preferably extends completely through the metallic flat conductor.The through-opening preferably extends along a surface normal over a wide surface. The through-opening can be a punched or drilled opening.

[0010] A metallic flat conductor can be a power conductor, a battery cell connector, a module connector, a terminal, a crimp terminal, or the like. A metallic flat conductor can be used in automotive applications, for example, as a power conductor, battery conductor, or similar. In a motor vehicle, a metallic flat conductor can connect a battery to a powertrain, a starter and / or generator, power electronics, or a drive motor, or connect electrical components to each other.

[0011] An electrical component is preferably connected to the metallic flat conductor. This can be an electrical component, a conductor, in particular a round conductor, a flexible conductor, in particular a flexible round conductor, or the like. The connection arrangement has at least one contact element for connecting such electrical components. A connecting bolt is arranged in a through-opening of the contact element, via which the contact elements are connected to other components. For example, two contact elements are arranged at opposite ends of the flat conductor, whereby an electrical connection between two connection points of a motor vehicle contacted at the contact elements can be provided via the flat conductor.

[0012] According to the invention, the connection arrangement comprises a metallic flat conductor with at least one through-hole. In the region of the through-hole, a metallic contact element is bonded to the flat conductor. A connecting bolt is arranged in the through-hole of the contact element, which extends at least partially, preferably completely, through the through-hole of the contact element. The through-hole of the contact element has an interference fit, meaning it is oversized relative to the bolt arranged in the through-hole. This means that the clear opening of the through-hole significantly exceeds the diameter of the connecting bolt. "Significantly exceeds" in this context means that the interference fit of the through-hole deviates from the diameter of the connecting bolt to a degree that exceeds usual manufacturing tolerances.

[0013] Due to the oversized opening of the contact element compared to the connecting bolt, the connecting pin can be displaced within the opening. This allows for improved tolerance compensation when installing the connection arrangement in a motor vehicle, which significantly simplifies assembly, particularly with complexly bent flat conductors. This eliminates the need for manual re-bending of the flat conductor into its installation position, which is difficult with large conductor cross-sections.

[0014] A metallic contact element is arranged in the area of ​​the through-hole of the flat conductor. "In the area of ​​the through-hole" in this context means that the contact element is located adjacent to the through-hole of the flat conductor. The metallic contact element has a through-hole that preferably overlaps at least partially with the through-hole of the flat conductor. A connecting bolt is inserted into the through-hole of the contact element, extending at least partially through this through-hole. Preferably, the contact element extends partially, and more preferably completely, through the through-hole of the flat conductor.

[0015] The through-hole of the metallic contact element has an interference of at least 1.0 mm, preferably at least 1.5 mm, at least 2.0 mm, at least 2.5 mm, at least 3.0 mm, at least 3.5 mm, at least 4.0 mm, or at least 4.5 mm, and in particular 1.5 mm to 5.0 mm, for example, 2.5 mm. The values ​​mentioned refer to total values, so that, for example, a terminal bolt placed centrally in a through-hole with an interference of 2.0 mm has a distance of 1.0 mm from the through-hole of the contact element at two opposite points on its outer surface. A particularly advantageous tolerance compensation takes place in these areas. The through-hole of the metallic contact element is a through-hole whose projection onto the plane of the flat conductor at least partially overlaps with the through-hole of the flat conductor.Preferably, the projection of the contact element's through-hole into the plane of the flat conductor lies entirely within the flat conductor's through-hole. The contact element's through-hole can be symmetrical or asymmetrical. If the contact element's through-hole is asymmetrical, the interference is present in at least two dimensions.

[0016] Preferably, the contact element is designed as a bolt that is bonded to the flat conductor in the area of ​​the through-hole. The bolt can be understood as a longitudinally extending bolt with two distal end faces. One end face forms the bolt shaft, and the other forms a bolt head. The bolt shaft and bolt head together constitute the contact element. The bolt shaft preferably has a smaller diameter than the bolt head; however, the bolt head and bolt shaft can also have the same diameter. If the bolt head has a larger diameter than the bolt shaft, the bolt head projects radially outward from the bolt shaft. This results in a third end face of the bolt, which is located on the surface of the bolt head adjacent to the bolt shaft.The bolt shaft of the contact element is preferably inserted into the through-hole of the flat conductor and bonded to it in the area of ​​the through-hole, while the surface of the bolt head facing the flat conductor is bonded to the adjacent surface of the flat conductor. The radially projecting bolt head limits the insertion depth of the contact element in the through-hole of the flat conductor, as the bolt head acts as a stop. In a friction welding process, the contact element is preferably welded in the area of ​​the contact surface between the flat conductor and the bolt head of the contact element by means of friction welding.

[0017] The bolt head of the contact element is preferably formed as a flange and serves both as a contact surface against the flat conductor and as an enlarged bearing surface for the connection assembly. The contact surface is the surface facing the flat conductor. The bearing surface is the surface opposite it. The bearing surface is preferably shaped as a flat surface. A head of the connecting bolt, a nut screwed onto the connecting bolt, or a washer can rest on the surface of the flange facing away from the flat conductor. Preferably, the connecting bolt is inserted into the through-hole of the flat conductor at a shaft-side end face of the contact element, so that the shaft of the connecting bolt protrudes partially from the bolt head of the contact element.The contact surface of the contact element preferably serves for electrical contact, and further electrical components of the vehicle, such as another flat conductor, can be contacted to it. The contact surface can be round, rectangular, square, polygonal, or the like. Along its circumference, the contact surface can have areas that project further outwards and areas that project less far outwards.

[0018] In a preferred embodiment, the oversize of the through-hole of the contact element is constant around the center of the surface of the through-hole in the area of ​​the bolt head of the contact element. A connecting bolt inserted at the center of the surface of the through-hole of the contact element therefore initially has the same oversize relative to the through-hole and can be moved equally in all directions during assembly of the connection arrangement in the vehicle and fixed in this position.

[0019] In a further preferred embodiment, the interference in the area of ​​the bolt head is variable around the circumference of the inserted connecting bolt. This means that the distance between the center of the through-hole of the bolt head and the nearest wall section of the contact element is not constant around the center of the surface. The circumferential edge of the through-hole is particularly preferably offset in at least one section from the envelope of the circumferential edge towards the center of the through-hole. This has the advantage that the possible contact area between an electrical component fixed to the bearing surface of the bolt head of the contact element via the connecting bolt and the bolt head of the contact element is increased, thereby improving the electrical contact.Even in embodiments where electrical contact is not made via the bearing surface of the bolt head of the contact element, the enlarged bearing surface offers the advantage of improved mechanical contact.

[0020] Preferred embodiments for increasing the electrical contact area of ​​the contact element include bolt heads whose through-holes have a polygonal geometry of their outer surface. For example, star-shaped through-holes and through-holes with outer contours in the form of several overlapping circles have proven advantageous. In these designs, portions of the bolt head's surface extend far towards the center of the through-hole, thus advantageously maximizing the contact area. In a particularly preferred embodiment, the through-hole is designed as a triangle, square, or hexagon, especially a hexagon. These geometries allow for a larger electrical contact area compared to a circular envelope and are also easier to manufacture than more complex polygonal geometries.

[0021] The diameter of the through-hole can be either constant or variable along the contact element, i.e., in the section between the two distal end faces of the contact element. The interference fit along the contact element is therefore also configured as either constant or variable.

[0022] For ease of manufacture, contact elements with a constant through-hole have proven preferable. Particularly in contact elements with a polygonal through-hole, for example in the form of a hexagon, this through-hole is preferably designed with a constant diameter between the two opposing end faces of the contact element. This allows a connecting bolt that passes completely through the contact element to be moved across its entire cross-section. Furthermore, a polygonal through-hole can also be used as an internal drive for a friction welding tool. In this respect as well, a continuous polygonal opening is advantageous to provide the largest possible contact area for the friction welding tool.

[0023] The contact element can be designed as either a single piece or in multiple parts. A single-piece design is particularly advantageous for contact elements with a simple geometry, such as a contact element with a cylindrical through-hole of constant diameter. Multi-part designs have proven advantageous when the through-hole of the contact element has a variable diameter. In such cases, for example, the bolt head of the contact element can be configured as the first component and the bolt shank as the second component, and the cross-section of the through-hole in the first component can differ from that in the second component.

[0024] In an advantageous embodiment of the connection arrangement according to the invention, the contact element comprises a first disc-shaped component and a second sleeve-shaped component. The second sleeve-shaped component is tubular with a through-opening extending longitudinally along the second component. The first disc-shaped component also has a through-opening. The first disc-shaped component can, for example, be placed on the flat part and optionally welded to it, with the second component being inserted into the through-opening on the side of the flat part opposite the first component. A material-bonded connection between the components and with the flat conductor can then be achieved by friction welding, whereby the second component is set into rotation using a friction welding tool.This rotation allows a material bond to be formed between an end face of the second component and a surface of the first component, and also between the outer surface of the second component and the inner surface of the through-hole of the flat conductor.

[0025] The first component is preferably aligned with the second component such that a center point of the first component aligns with the center point of the second component. The through-opening of the first component and the through-opening of the second component are at least partially congruent with each other, with a center point of the through-opening of the first component particularly preferably aligning with a center point of the through-opening of the second component. The through-opening of the first component and the through-opening of the second component together form the through-opening of the contact element.If a connecting bolt is inserted through the at least partially overlapping through-openings of the first and second components, the interference is present in the area of ​​both through-openings, whereby the extent of the interference can vary within the through-opening of the first component and / or in the area of ​​the through-opening of the second component. For example, the through-opening of the first component has a different cross-section than the through-opening of the second component. For example, a projection of the cross-section of the through-opening of the first component onto the plane of the second component lies within the cross-section of the through-opening of the second component. The sleeve-shaped second component preferably has a cylindrical through-opening that can be manufactured in a simple manner.The disc-shaped first component can also be provided by means of punching, for example, in the case of non-cylindrical, more complex geometries of the through-hole.

[0026] Preferably, the connecting bolt of the connection arrangement has a bolt shaft and a bolt head, wherein the bolt head of the connecting bolt rests against the shaft-side end face of the contact element.

[0027] In a preferred embodiment, the connecting bolt has an external thread, which enables improved mechanical fixing, for example by locking the connecting bolt with a nut.

[0028] In a preferred embodiment, the connection arrangement has at least one second metallic contact element. This second metallic contact element may be designed differently from the first, for example, as a bolt whose end face opposite the shaft is welded to the flat conductor. The second contact element may also be shaped analogously to the first. Preferably, at least one of the second contact elements is bonded to the flat conductor in the region of a second through-opening, wherein the second contact element has a through-opening and a connecting bolt, at least partially penetrating the through-opening, is inserted into this opening.In particular, the connecting bolt that passes through the opening of the second contact element is selected such that the opening of the second contact element has an interference fit with the connecting bolt. This allows for tolerance compensation at several connection points of the connection assembly. This is particularly advantageous for flat conductors with a large cross-section and the associated low flexibility.

[0029] The connection arrangement preferably comprises a first and a second contact element, both of whose through-holes have an interference fit with the respective connecting bolt, wherein the second contact element is not arranged at a distal end of the flat conductor, but forms an additional electrical and mechanical contact point in the central region of the flat conductor. A third contact element can be arranged at a distal end of the flat conductor, which can be configured in the same way as the first contact element or differently. The second contact element lies along one of the main surfaces of the flat conductor between the first and third contact elements.

[0030] Preferably, the first contact element and the second contact element are arranged at a distance of a maximum of 1000 mm, preferably a maximum of 700 mm, in particular a maximum of 500 mm, for example 100 mm to 400 mm, from each other, wherein the total length of the flat conductor exceeds the distance between the first contact element and the second contact element by at least a factor of 1.1.

[0031] The first and second contact elements are preferably arranged within the specified dimensions at a small distance from each other, with the second contact element forming a center tap, i.e., not arranged at the ends, and the flat conductor particularly preferably having a length of at least 1500 mm. As the length of the flat conductor increases, so does the need for tolerance compensation, especially with more than two contact points. In the prior art, this is generally achieved by combining a flat conductor with a flexible conductor connected to its ends. If more than two contact points are provided, the flat conductor is generally positioned between an end and a center contact point, and the center contact point is connected to the remaining end contact point via a flexible conductor.This known method of tolerance compensation entails increased production and assembly costs. The invention provides a remedy by performing tolerance compensation on one or, preferably, several contact elements.

[0032] Preferably, the flat conductor has at least one bend between the first contact element and the second contact element, which is arranged in a central area. In particular, the first and second contact elements lie in different planes, which may be parallel or non-parallel to each other. To compensate for the manufacturing tolerances associated with the bends in the flat conductor, the use of contact elements with an interference fit relative to the connecting bolts has proven advantageous.

[0033] The second contact element and any further contact elements are preferably designed within the embodiments described for the contact element, wherein the degree of interference between the contact element and the second and further contact elements may differ.

[0034] If a contact element is arranged at a distal end of a flat conductor, it is located at a distance of no more than 100 mm, preferably no more than 50 mm, from this end, with no further contact element located between it and the distal end. A contact element in a central region of the flat conductor is not located at a distal end of the flat conductor.

[0035] The flat conductor of the connection arrangement preferably has a bend, in particular a complex bending geometry. The flat conductor is bent at at least one location, preferably at least two locations, and in particular at least three locations, for example at least four, at least five, or at least six locations. In an advantageous embodiment, the flat conductor has at least one bend with a bending angle of at least 30°, preferably at least 40°, and in particular at least 90°, at least 120°, or at least 150°. For example, the flat conductor has at least two bends, wherein at least one of the bends has a bending angle of at least 90° and at least one of the bends has a bending angle of at least 120°, preferably at least 150°.In particular, the flat conductor has at least two bends in at least two different dimensions (x and y, x and z, or y and z), preferably at least three different dimensions (x, y, and z). The installation of connection arrangements with such complexly bent flat conductors is simplified by the connection arrangement according to the invention.

[0036] The flat conductor preferably has a length of at least 700 mm, more preferably at least 1000 mm, particularly preferably at least 1500 mm, and especially at least 2000 mm, measured in the straight state or when measured in the bent state along one of the main surfaces between the distal end faces of the flat conductor. For example, the length of the flat conductor is between 1500 mm and 3000 mm. As the length of the flat conductor increases, the total manufacturing tolerances occurring between two distal contact elements of the flat conductor also increase. Furthermore, in motor vehicles, the tolerances between two electrical contact points are also greater the further apart they are. Thus, the connection arrangement according to the invention is particularly suitable for use with long flat conductors.

[0037] The cross-section of the flat conductor is preferably at least 50 mm² or at least 75 mm², particularly preferably at least 100 mm², and in particular at least 120 mm², for example 100 mm² to 400 mm². The connection arrangement according to the invention is particularly advantageous when using flat conductors with large cross-sections. With increasing cross-section and the associated bending stiffness of the flat conductor, tolerances can no longer be compensated for by manual bending, whereas the connection arrangement according to the invention can effect this necessary tolerance compensation.

[0038] The flat conductor preferably comprises aluminium, an aluminium alloy, copper and / or a copper alloy.

[0039] The contact element and / or the connecting bolt are preferably made of aluminium, an aluminium alloy, copper, a copper alloy, iron, an iron alloy and / or steel.

[0040] Preferably, the materials of the first contact element and / or the connecting bolt are selected to have a greater strength than the material of the flat conductor. The materials of the first and second contact elements exhibit an elastic limit Rp0.2 that is greater than the elastic limit of the flat conductor material.

[0041] The contact element, and optionally the second contact element, is bonded to the flat conductor by a material connection, preferably soldered or welded, and particularly preferably by friction welding, rotary friction welding, ultrasonic welding, pressure welding, resistance welding, or laser welding, especially rotary friction welding. The welding between the flat conductor and the contact element results in a low electrical contact resistance, allowing the contact element to serve as an electrical connection component.

[0042] Rotary friction welding has proven particularly advantageous. This friction welding can also be ultrasonic welding. In rotary friction welding, the stud is set into oscillation or rotation relative to the flat conductor. This is achieved by applying pressure to the flat conductor with the contact element, whereby a contact surface of the contact element, while simultaneously moving relative to its longitudinal axis, is pressed against a surface of the flat conductor. This introduces frictional heat into the interface between the contact element and the flat conductor in the area of ​​the contact element's contact surface. The frictional heat causes at least one material at the interface between the flat conductor and the contact element to plasticize. The plasticized materials bond together and form a metallurgical connection.

[0043] In friction welding, contact elements are preferably welded to the flat conductor in the area of ​​the contact surface. Applying pressure to the contact elements presses the welding surface of the contact element against the conductor surface. The welding surfaces of the contact elements preferably feature recesses and / or protrusions and / or relief-like structures. These features result in a small contact area on the flat conductor at the start of the welding process, thus achieving higher temperatures with the same contact pressure.

[0044] For rotary friction welding, it is advantageous if the contact element and / or the second contact element is axially symmetrical about its longitudinal axis. The contact element and / or the second contact element can be rotationally symmetrical, axially symmetrical, elliptical, or similar with respect to its longitudinal axis. In the case of a non-rotationally symmetrical shape, the contact element and / or the second contact element can be used as an external drive. This means that a rotary friction welding tool can be positioned on the outer circumference of the contact element and impart a rotation to it. This rotation can then weld the contact element to the flat part. Particularly preferably, the contact element has a section comprising a polygonal envelope, which serves as a point of contact for a friction welding tool.Preferred shapes are polygons that approximate the circular shape, for example hexagons, octagons, decagons or dodecagons.

[0045] According to one embodiment, it is proposed that the first contact element and / or the second contact element be metallically coated. A metallic coating can be applied to the material of the contact element. This can be done using a wet chemical process. Depending on the specific application, and in particular on the material of the flat conductor and / or the material of the electrical component to be attached to the contact element, it may be advantageous to coat the first contact element and the second contact element with one or, in certain sections, with different metallic materials. In particular, the first and / or the second contact element can each be coated only in certain areas, while other areas of the contact element remain uncoated.

[0046] It is proposed that a material for the coating be tin, gold, nickel, silver, copper, or an alloy thereof. In particular, electroplated nickel has proven advantageous for coating the first and / or second contact element, especially due to its ductility. A coating of pure nickel is preferably applied as the electroplated nickel. Nickel sulfamate is particularly preferred for electroplating.

[0047] A multi-layer, particularly two-layer, coating is also proposed. In this process, at least one contact element can be coated with a first metallic material in a first step, and in a second step, the coated contact element can be coated with a metallic material different from the first. It has been found that under-nickel plating is particularly advantageous. Here, at least one contact element is first coated with a nickel layer and / or a nickel alloy, especially a nickel-phosphorus alloy. The nickel-containing layer provides good mechanical protection for the contact element. A tin, gold, copper, silver, or alloy layer can then be applied over the nickel-containing layer.A nickel and tin undercoat can be advantageous, for example, if the contact element is subsequently soldered or welded to an electrical component. A tin layer can also be useful to provide a good electrical contact layer, and the tin layer does not need to be removed in the welding area. In particular, a coating with nickel, gold, copper, or silver—with nickel, copper, and silver being preferred for cost reasons—has proven advantageous in welding applications.

[0048] According to one embodiment, it is proposed that the coating have a maximum thickness of 10 µm. It has been found that such a layer thickness represents a good compromise between electrical conductivity at the electrical interface between the contact element and the flat conductor on the one hand, and mechanical stability and protection against environmental influences on the other. In particular, a single-layer coating, i.e., a coating comprising a homogeneous layer of a material, has a thickness of 1 µm to 10 µm, preferably 3 µm to 10 µm.

[0049] For a multilayer coating, a maximum coating thickness of 20 µm is proposed. A multilayer coating comprises several superimposed layers of different compositions. Preferably, each of the layers has a maximum thickness of 10 µm.

[0050] According to one embodiment, it is proposed that the first and / or the second contact element is welded to the flat conductor with a penetration depth of at least 0.2 mm, preferably between 0.2 mm and 2 mm, and particularly preferably between 0.2 mm and 1.5 mm. During welding, the contact element is pressed against the flat conductor with its side facing the flat conductor. Subsequently, the interface between the flat conductor and the contact element is plasticized by the application of welding energy. This can be achieved through frictional energy, electrical energy, or the like. During plasticization, a joining zone is created into which the contact element can penetrate. In particular, the material of the flat conductor can have a lower melting point than the material of the first contact element and / or the coating of the contact element, so that the material of the flat conductor plasticizes first. By applying pressure, the contact element can penetrate into the flat conductor.It has been found that a penetration depth of 0.2 mm to 2 mm is advantageous both mechanically and electrically. If the penetration depth is too shallow, the mechanical and electrical properties of the connection deteriorate. Very large penetration depths, on the other hand, require very high welding energy and, furthermore, can lead to mechanically disadvantageous connections when combined with thin flat conductors.

[0051] According to one embodiment, it is proposed that a surface of the contact element facing away from the flat conductor, also referred to as the first end face, protrudes from the surface of the flat conductor in the joined state. Preferably, the flat conductor has insulation, and the first and / or second contact element protrudes from the surface of the insulation facing away from the flat conductor. The contact element is preferably welded to the flat conductor only to such a depth that at least a portion of the contact element protrudes from the surface of the flat conductor, particularly the broad surface of the flat conductor. This prevents a mechanical or electrical component placed on the contact element from coming into direct contact with the flat conductor.

[0052] It is proposed that the contact element extends through a through-hole in the flat conductor. A second end face, opposite the first end face of the contact element, projects from the surface of the flat conductor on the side facing away from the first end face. The projection of the first and / or second end face of the contact element from the broad surface of the flat conductor is preferably between 0.1 mm and 1 mm. A minimum projection of 0.1 mm ensures that an electrical and / or mechanical component attached to the contact element does not come into direct contact with the flat conductor in the area of ​​the through-hole and the electrical contact element. In a preferred embodiment, the flat conductor has insulation, and the second end face projects at least 0.1 mm from the insulation on the broad surface of the flat conductor.

[0053] In a preferred embodiment, the connection arrangement comprises a second flat conductor with a through-hole, wherein optionally a second contact element with a through-hole is bonded to this through-hole. Depending on the material of the second flat conductor, it can also be screwed directly to the connecting bolt without the use of a contact element, e.g., via an internal thread located in the second flat conductor. In a preferred embodiment, the through-hole of the second flat conductor preferably also has an interference fit with the connecting bolt, as described for the first contact element. The connecting bolt is inserted into the contact element from the end face of the bolt shank of the contact element, so that the bolt shank of the connecting bolt projects beyond the bolt head of the contact element.The second flat conductor is arranged on the first flat conductor such that the through-hole of the contact element and the through-hole of the second flat conductor are at least partially aligned, and the connecting bolt passes through both through-holes. Preferably, the connecting bolt is secured against a surface of the second flat conductor facing away from the first by means of a nut or a retaining element. The end face of the bolt head of the contact element, facing away from the shaft, is in contact with the second flat conductor. The oversize of the through-hole of the contact element allows for advantageous tolerance compensation. In particular, if the through-hole of the contact element and the through-hole of the second flat conductor both have an oversize relative to the connecting bolt, this tolerance compensation can be further increased.The oversize of the through-hole of the contact element and the oversize of the through-hole of the second flat conductor can be the same or different with respect to the connecting bolt. The second flat conductor can be contacted directly or indirectly via a contact element.

[0054] In a particularly preferred embodiment, the connection arrangement comprises a second flat conductor with a second contact element having a through-hole, wherein the through-hole of the second contact element preferably also has an interference fit with the connecting bolt. Preferably, the second flat conductor and the second contact element are configured as described for the first flat conductor and the first contact element, whereby the second flat conductor and second contact element may have different configurations than the first flat conductor and first contact element. The connecting bolt is inserted into the contact element starting from the end face of the bolt shank of the contact element, so that the bolt shank of the connecting bolt projects beyond the bolt head of the contact element.The second flat conductor is arranged on the first flat conductor such that the through-holes of the first contact element and the second contact element are at least partially aligned, and the connecting bolt passes through both through-holes. Preferably, the connecting bolt is secured against a surface of the second flat conductor facing away from the first by means of a nut or a retaining element. The end faces of the bolt heads of the first and second contact elements, facing away from the shaft, are in contact with each other. The oversize of the through-hole of the first contact element allows for advantageous tolerance compensation. In particular, if the through-hole of the first contact element and the through-hole of the second contact element both have an oversize relative to the connecting bolt, this tolerance compensation can be further increased.The oversize of the through-hole of the contact element and the oversize of the through-hole of the second contact element, each in relation to the connecting bolt, can be the same or different.

[0055] In another preferred embodiment, the end face of the bolt head of the contact element facing away from the shaft provides an electrical contact surface for a battery connection.

[0056] Another aspect of the invention is a method according to claim 13 comprising at least the following steps: Providing a flat conductor, introducing at least one through-hole into the flat conductor, providing a metallic contact element comprising a through-hole, joining the contact element materially in the area of ​​the through-hole of the flat conductor and inserting a connecting bolt into the through-hole of the flat conductor, the through-hole has an excess size compared to the connecting bolt.

[0057] In a preferred embodiment, the contact element is made in two parts and comprises at least a first component and a second component, wherein the first component and the second component are joined to each other and to the flat conductor in any order by a material bond. Preferably, the first component is joined to the flat conductor independently of each other and the second component is joined to the flat conductor independently.

[0058] Preferably, the flat conductor is bent before or after preparation, particularly before preparation. In a preferred embodiment of the method, the flat conductor is bent at at least one, preferably at least two, and particularly at least three longitudinal sections. Preferably, the flat conductor is bent at at least one point by at least 30°, more preferably at least 40°, and in particular at least 90°, for example at least 120°.

[0059] The contact element is preferably press-welded, friction-welded, ultrasonically welded, laser-welded or resistance-welded to the flat conductor, particularly preferably rotary friction-welded or laser-welded.

[0060] In friction welding of the contact element, a friction welding tool is preferably applied as an external drive to the outer contour of the contact element. Contact elements with polygonal outer contours are particularly suitable for this purpose. In a further preferred embodiment, an internal drive of a friction welding tool is inserted into the through-hole of the first contact element and optionally into a through-hole of the second contact element. A torque can also be applied to the contact element particularly effectively via the elongated through-hole, thus effecting a weld.

[0061] The statements regarding the connection arrangement according to the invention also apply to the method according to the invention and vice versa.

[0062] The subject matter is explained in more detail below with reference to a drawing showing an exemplary embodiment. The drawings are not to scale and do not limit the invention in any way. The drawing shows: Fig. 1a,b Top views of a preferred embodiment of the connection arrangement according to the invention, Fig. 2a,b Cross-sectional views of a preferred embodiment of the connection arrangement according to the invention, Fig. 3a,b Cross-sectional views of another preferred embodiment of the connection arrangement according to the invention, Fig. 4a Schematic representations of various embodiments of the through-opening of the bolt head of the contact element in top view, Fig. 5 A schematic exploded view of a physical connection arrangement in the area of ​​the contact element, Fig. 6 An embodiment of a contact element in longitudinal section and Fig. 7 A connection arrangement comprising two contact elements.

[0063] Figures 1a and 1bThe figures show top views of a preferred embodiment of the connection arrangement 100 according to the invention. The connection arrangement 100 comprises a bent aluminum flat conductor 1 with insulation 20 removed from both end regions of the flat conductor 1. In the stripped region, a contact element 3 is bonded to the flat conductor 1 by a material bond. The contact element 3 comprises copper and is attached to one of the wide surfaces of the flat conductor 1 by friction welding. The contact element 3 is arranged in a through-opening 2 of the flat conductor 1 and is designed as a bolt with a through-opening 5. Figure 1a Figure 1 shows the through-opening 5 of the contact element 3, into which a connecting bolt 4 is inserted. The contact element 3 is designed as a bolt with a bolt head 8 and a bolt shank 7, wherein Figure 1aA top view of the bolt head 8 is shown. The connecting bolt 4 is inserted into the contact element 3 from the end face of the bolt shaft 7 opposite the bolt head 8, so that in Figure 1a Only the front face of the bolt shaft of the connecting bolt 4 is visible. Figure 1b Figure 1 shows a top view of the opposite main surface of the flat conductor 1, where the bolt head of the connecting bolt 4, inserted into the contact element 3, is visible. The end face of the bolt shaft 7 of the contact element 3 is not visible, as it is covered by the connecting bolt 4.

[0064] The connecting bolt 4 is slidably arranged in the through-opening 5 of the contact element 3, thus enabling displacement along the x- and y-directions and thereby compensating for tolerances in two dimensions, thereby facilitating the assembly of the connection arrangement 100 in a motor vehicle. The through-opening 5 is, for example, cylindrical.

[0065] Figures 2a and 2b Figure 1 shows cross-sectional views of a preferred embodiment of the connection arrangement 100. The first contact element 3 is as shown in Figure 2. Figure 2aThe contact element 3 is shown as a bolt with a through-hole 5 and is mounted in a through-hole 2 of the flat conductor 1, with the connecting bolt 4 being inserted into the through-hole 5 of the contact element 3. The through-hole 5 of the contact element 3 has an interference of 2.5 mm with respect to the connecting bolt 4 inserted therein, the through-hole 5 having a diameter of 6.5 mm and the connecting bolt having a diameter of 4.0 mm. The connecting bolt 4 extends through the through-hole 5 and can be secured on the surface of the flat conductor 1 facing away from the bolt head of the connecting bolt 4 by a nut (not shown) or a retaining element, which rests on the bolt head 8 of the contact element 3. In a preferred embodiment, a second flat conductor with a contact element 3 is placed on the end face of the bolt head 8 of the contact element 3 facing away from the shaft and electrically contacted via this end face of the bolt head 8.The connecting bolt 4 preferably also extends through a through-opening of the second flat conductor and is secured against the surface of the second flat conductor facing away from the bolt head 8. In a further preferred embodiment, the end face of the bolt head of the contact element provides a connection surface for a battery. Preferably, the through-opening 5 has a circular, hexagonal, or octagonal shape. Polygonal geometries, such as octagonal or hexagonal shapes, are advantageous for using an internal drive of the rotary friction welding tool when welding the contact element 3 to the flat conductor 1.

[0066] Figures 3a and 3b Figure 1 shows cross-sectional views of another preferred embodiment of the connection arrangement 100. The contact element 3 is as shown in Figure 2. Figure 2a shown as a bolt with a through-opening 5 and installed in a through-opening 2 of the flat conductor 1, wherein according to Figure 3b The connecting bolt 4 is inserted into the through-opening 5 of the contact element 3. In contrast to the embodiment of the Figures 2a and 2b is in the Figures 3a and 3b The contact element 3 is designed in two parts. According to the Figures 3a and 3b The contact element 3 comprises a first disc-shaped component 14 and a second sleeve-shaped component 15, the mutually aligned openings of which form the through-opening 5. A two-part embodiment of the contact element 3 is advantageous in order to realize different geometries of the through-opening 5 in the area of ​​the disc-shaped first component 14, which forms the bolt head, and the sleeve-shaped second component 15, which forms the bolt shank. Preferably, the bolt head 8 of the contact element 3, formed by the disc-shaped first component, is as shown in Figures 4a-idescribed, while the sleeve-shaped second component 15 has a cylindrical through-opening which preferably corresponds in its diameter to the envelope of the through-opening of the bolt head and is arranged congruently to the through-opening of the bolt head.

[0067] Figures 4a to 4i The schematic representations of various embodiments of the contact element 3 are shown in a top view of the bolt head 8. According to the Figures 4a-iThe respective edges that bound the lateral surface 6 and the through-opening 5 are shown. The lateral surface 6 is shown as a hexagon, but can also assume any other geometry, with circular and polygonal geometries approximating the circular shape, such as hexagons, octagons, or decagons, being preferred. The edges 5a of the through-opening 5 can be straight or curved. The through-opening 5 is polygonal, with several edge segments 5a offset towards the center of the surface of the through-opening 5, starting from a circular envelope of the through-opening 5. This increases the contact area of ​​a component resting on the bolt head 8, such as a battery terminal or another flat conductor with or without a contact element, with the contact element 3.

[0068] Figure 5shows a schematic exploded view of a physical connection arrangement in the area of ​​the contact element 3 and the connecting bolt 4 inserted therein. Figure 5 Figure 1 shows a flat part 1 and the contact element 3, which is designed as a bolt with a through-hole 5. The contact element 3 is shown here as a single piece, but can also be made in multiple parts according to Figure 1. Figures 3aThe contact element 3 is designed as a bolt comprising a bolt head 8 and a bolt shank 7. The bolt head 8 has a shaft-facing end face 9c facing away from the bolt shank 7 and a shaft-facing end face 9b facing the bolt head 7, while the bolt shank 7 has an end face 9a. The contact element 3 is inserted through the through opening 2 with its bolt shank 7. The shaft-facing end face 9b of the bolt head 8 is bonded to the flat part 1. The length of the bolt shank 7 can be at least equal to the height of the flat part 1. Thus, the bolt shank 7 can be fully inserted into the through opening 2. Preferably, the bolt shank 7 protrudes from the wide surface of the flat conductor 1 on the side opposite the bolt head 8.The contact element 3 has a through-opening 5 extending from the end face 9c of the bolt head (away from the shaft) to the end face 9a of the bolt shaft. The through-opening 5 has a diameter of 6.5 mm and is penetrated longitudinally by a connecting bolt 4 with a diameter of 4.0 mm, such that the through-opening 5 is larger than the connecting bolt 4. The connecting bolt 4 comprises a bolt head 10 and a bolt shaft 11, the bolt shaft 11 being inserted into the through-opening 5 and the bolt head 10 bearing against the end face 9a of the bolt shaft 7 of the contact element 3 with its shaft-side end face.

[0069] Figure 6Figure 1 shows an embodiment of the contact element 3 in longitudinal section. The contact element 3 is formed in the form of a bolt with a bolt head 8 and a bolt shank 7. The bolt head 8 has an end face 9c facing away from the bolt shank 7 and an end face 9b facing towards the bolt head 7, while the bolt shank has an end face 9a. The bolt head 8 has a diameter that tapers along its longitudinal axis. The end face 9b of the bolt head 8 is frustoconical. The end face 12 has an angle of inclination 12 to a plane perpendicular to the longitudinal axis of the contact element 3 of between 1° and 10°, preferably 5°. During welding, the end face 9b initially rests against the flat part 1 in the area of ​​the bolt shank 7. During welding, the frustoconical shape of the end face 9b gradually penetrates the flat part 1. The plasticized material is displaced radially outwards.A relief groove 13 can be provided at the transition between the bolt shank 7 and the bolt head 8. The relief groove 13 ensures that the end face 9b can rest fully on the flat conductor 1. The relief groove 13 removes any impurities at the transition between the bolt shank 7 and the bolt head 8, so that when the end face 9b is placed on the flat conductor 1, it can rest directly and fully on it without any interfering material being present at this transition.

[0070] Figure 7Figure 1 shows a connection arrangement 100 comprising a contact element 3 with a through-opening 5, which is materially bonded to a distal end 17a of the flat conductor 1. A second contact element 3 with a through-opening 5 is arranged in a central region 17b of the flat conductor 1. Between the two contact elements 3 are two bends 16 of the flat conductor 1, such that the contact elements 3 lie in different, mutually parallel planes. The contact elements 3 are designed as shown in Figure 1. Figures 1 to 6 The described system is characterized by the through-holes 5 having an interference fit with a connecting bolt (not shown) passing through them. The contact elements 3 are, for example, spaced 150 mm apart, measured along a main surface of the flat conductor 1. A further distal end of the flat conductor 1 is not shown. A contact element 3 is preferably also attached to this end of the flat conductor (not shown). Reference sign

[0071] 100 connection arrangement 1 Flat conductor 2 Through-hole of the flat conductor 1 3 Metallic contact element 4 Metallic connecting bolt 5 Through-hole of the metallic contact element 5a Circumferential edge of the through-hole 5 6 Sheath of the contact element 7 Bolt shank of the contact element 3 8 Bolt head of the contact element 3 9 End faces 9a End face of the bolt shank 9b End face of the bolt head facing the shank 9c End face of the bolt head facing away from the shank 10 Bolt head of the connecting bolt 4 11 Bolt shank of the connecting bolt 4 12 Chamfer 13 Fillet, groove 14 Disc-shaped component of the metallic contact element 3 15 Sleeve-shaped component of the metallic contact element 3 16 Bends 17 Axial end of the flat conductor 1 17b Middle area of ​​the flat conductor 1

Claims

1. Connection arrangement (100) comprising at least: - a metallic flat conductor (1) with a through-opening (2), - a metallic contact element (3) with a through-opening (5) that is bonded to the flat conductor (1) in the area of ​​the through-opening (2), - a connecting bolt (4) that at least partially extends through the through-opening (5) of the metallic contact element (3), characterized by - that the through-hole (5) of the metallic contact element (3) has an excess size relative to the connecting bolt (4).

2. Connection arrangement (100) according to claim 1, characterized by that the through-hole (5) of the metallic contact element (3) has an excess of at least 1.0 mm, preferably at least 2.0 mm, in particular 1.5 mm to 5.0 mm.

3. Connection arrangement (100) according to claim 1 or 2, characterized by - thatthe metallic contact element (3) is formed as a bolt comprising a bolt head (8) and a bolt shaft (7) and the bolt shaft (7) engages in the through-opening (2) of the flat conductor (1).

4. Connection arrangement (100) according to claim 3, characterized by - that the excess of the through-opening (5) of the contact element (3) in the area of ​​the bolt head (7) is variable around the circumference of the connecting bolt (4), preferably that the circumferential edge (5a) of the through-opening (5) is offset in at least one section from the envelope of the circumferential edge (5a) towards the center of the surface of the through-opening (5).

5. Connection arrangement (100) according to one of the preceding claims, characterized by - that the excess length along the through-opening (5) is variable.

6. Connection arrangement (100) according to one of the preceding claims, characterized by - thatthe metallic contact element (3) is arranged at a distal end of the flat conductor (1) and the connection arrangement (100) comprises a second contact element (3) which is arranged in a middle section of the flat conductor (1).

7. Connection arrangement (100) according to claim 6, characterized by - that the contact element (3) and the second contact element (3) are located in different planes of the flat conductor (1) and preferably have a maximum distance of 400 mm.

8. Connection arrangement (100) according to one of the preceding claims, characterized by - that the flat conductor (1) has at least one bend, preferably at least two bends.

9. Connection arrangement (100) according to one of the preceding claims, characterized by - that the flat conductor (1) comprises aluminium or copper.

10. Connection arrangement (100) according to one of the preceding claims, characterized by - thatthe metallic contact element (3) and / or the connecting bolt (4) is made of aluminium or an aluminium alloy, or of copper or a copper alloy, or of iron or an iron alloy, in particular steel.

11. Connection arrangement (100) according to one of the preceding claims, characterized by - that the contact element (3) is welded to the flat conductor (1), preferably press-welded, friction-welded, ultrasonically welded, laser-welded or resistance-welded.

12. Connection arrangement (100) according to one of the preceding claims, characterized by - that the contact element (3) is metallically coated, preferably with tin, gold, nickel, silver, copper or an alloy thereof, in particular with a nickel-phosphorus alloy.

13. Method for manufacturing a connection arrangement according to one of the preceding claims, in which - a flat conductor is provided, - at least one through-hole is provided in the flat conductor, - a metallic contact element comprising a through-hole is provided, - the first contact element is joined materially in the area of ​​the through-hole of the flat conductor, and - a connecting bolt is guided through the through-hole of the first contact element, wherein the through-hole of the contact element has an interference with the connecting bolt.

14. Method according to claim 13, wherein the flat conductor is bent before or after provision, preferably bent at least 90° at one point.

15. Method according to claim 13 or 14, wherein the contact element is press-welded, friction-welded, ultrasonically welded, laser-welded or resistance-welded to the flat conductor, preferably rotary friction-welded or laser-welded.

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