WO2018024784A1

WO2018024784A1 - Electrical connection assembly having tear-off protection function

Info

Publication number: WO2018024784A1
Application number: PCT/EP2017/069557
Authority: WO
Inventors: Volker Geitner; Patrick Limmer; Anna Regensburg; René Schürer
Original assignee: Electronicon Kondensatoren Gmbh
Priority date: 2016-08-04
Filing date: 2017-08-02
Publication date: 2018-02-08
Also published as: DE102016117220B3; CN109564820B; CN109564820A

Abstract

The invention relates to an electrical connection assembly having tear-off protection functions, in particular for capacitors or similar electrical or electronic components, wherein the connection consists of a stiff, wire-shaped first connection element and a thin-walled, band- or strip-shaped, plate- or film-shaped second connecting element, there being an integral bond between the first and second connecting elements at a contacting and connection point, wherein the contacting and connection point is realized by friction stir welding and the friction stir welding connection region forms a mechanical tear-off protection means having a defined tear-off force and a high capacity for carrying pulse currents.

Description

Electrical connection arrangement with tear-off function

description

The invention relates to an electrical connection arrangement with tear-off function, in particular for capacitors or the like electrical or electronic components, wherein the compound consists of a stiff, wire-shaped, first and a thin-walled, band or strip-like, sheet-like or foil-shaped, second connecting element and between the first and the second connection element is present at a contact and connection point according to the preamble of claim 1.

From DE 213 092 AI electrical capacitors are also larger

Reactive power previously known, which have a shutdown. According to the local task a shutdown protection is proposed, which is characterized by the fact that the heat loss generated in it remains small and that at lower switching power at the same time a safe shutdown of the network is possible. This is achieved in that the shutdown protection formed from conductor material of a sheet-shaped and up to a required

Cross section of the current is formed according to cut strips, wherein a partial strip is bent by 180 °, that this under tensile load due to an overpressure in the condenser of a

Separation is subject, so that at the same time the defective capacitor is disconnected from the power source.

For example, from the DD 114 165 AI is the basic principle of

Abreißsicherungen previously known, in which a predetermined breaking point with reduced cross-section is achieved, which is achieved by squeezing or removal of a portion of the cross-sectional area of a conductor.

A disadvantage of such predetermined breaking points is the fact that a Stromengstelle is created by the cross-sectional reduction, the one Resistance increase and thus additional power heat losses result.

In the electrical capacitor with low intrinsic inductance according to DD 264 781 AI are used as connecting elements between

the capacitor winding and the outer terminals strip or band-shaped conductor used, which are applied at the level of the upper contact layer on both sides on a protruding insulating support and can be guided as a strip conductor to the outer terminals. As connections to the band-shaped conductors are provided at right angles threaded threaded contact pieces. In the embodiment according to DD 264781 AI overpressure breakaway is realized, for which purpose a predetermined breaking point, for example in the form of a notch or a punched hole is introduced in the band-shaped conductor. In the condenser cup is a compressed bead, which opens at pressure and thus causes a housing extension and the tearing off of the relevant conductor.

In the capacitor with breakaway to CH 472103 is the

Tear-off at its protruding from the condenser housing cover end deformed such that the protruding end of the wire is taken along with a stretch of the housing from the lid.

The relevant outstanding end of the tear-off wire is bent in one embodiment and squeezed in another variant.

Solutions are still known for welding copper and

Copper alloys. The so-called friction stir welding is a process in which the process heat and the necessary pressure is generated by a tool by rotation. The tool consists of a rotating pin on which a pin can be centrally mounted. The pin is usually shorter than the material thickness to be welded and is pressed in rotation into the abutting surfaces of the workpieces. The same are fastened against each other and on a support to the

to absorb acting forces. Similar to friction welding, the material is plasticized due to the generated frictional heat and then transported up and out by the tool. By the Underlay and the end face of the tool pin, the weld metal remains trapped in the shock and forms the weld. With such a method both line and punctiform connections in butt and lap joint are possible. A tool for producing such Reibschweißverbindungen is disclosed for example in DE 10 2012 112413 AI. With the previously known tool, a Reibschweißverbindung between a wire and the substrate can be realized, in addition, the application of ultrasonic energy is required. After deformation and at the beginning or during the execution of the ultrasonic bending oscillations, there is a contact auxiliary surface which does not touch the wire at the time the ultrasonic source is activated, as a result of another

Deformation of the wire and / or further lowering of the

Tool in the direction of the substrate to the wire. This is intended to improve the connection quality and thus the result of the friction welding.

From the foregoing, it is an object of the invention to provide a further developed electrical connection arrangement with Abreißsicherungs- function, especially for capacitors or the like electrical or electronic components, the connection should have a high current carrying capacity and thus pulse current resistance on the one hand and on the other hand with the application of defined forces a safe achievement of the desired tear function is possible. A thermally induced destruction of the electrical connection, for example, if there is a high pulse current load in the capacitor as a result of short circuits, should be prevented. In this respect, the invention has the task, the contradiction between a high

Current carrying capacity and one necessary for the tear function

secure electrical separation point, on the other hand, however, to ensure that a secure Abreißfunktion is given, without too high forces acting on the separation point or that there is a need to provide in this regard force-enhancing measures that increase the cost of such Abreißsicherung. A further problem to be solved according to the invention is that the electrical connection arrangement starts from a stiff, wire-shaped, first connection element which is to be contacted with a second connection element which, in contrast, is thin-walled, band-shaped or strip-shaped or sheet-shaped or foil-shaped. Thus, the elements to be joined have completely different properties with respect to their stability, which meant that in the prior art usually large-area solder joints between the wire-shaped conductor and the band-shaped connection strip were realized and the conductor mentioned above notch was formed with tear function, with the disadvantage the resulting Stromengstelle.

The solution of the object of the invention is carried out with the electric

Connecting arrangement according to the feature combination according to

Claim 1, wherein the dependent claims comprise at least expedient refinements and developments.

The invention is therefore based on an electrical connection arrangement with a tear-off function, in particular for capacitors or similar electrical or electronic components. The connection comprises a first, rigid, wire-shaped connecting element and a second, band-like or strip-like, sheet-like or foil-shaped, thin-walled second

Connecting element. Between the first and the second connecting element, a contact and connection point is created by material connection.

According to the invention, the contact and connection point is realized by friction stir welding, wherein the friction stir welding connection region forms a mechanical breakaway protection with a defined pull-off force and high pulsed current carrying capacity.

A first basic idea is therefore the application of the known friction stir welding for the formation of an electrical connection arrangement with anti-tearing function, wherein according to the further inventive concept, the actual friction stir welding connection represents the tear-off. The thus created current-carrying connection between the wire-shaped conductor on the one hand and band-shaped conductor on the other hand is particularly useful and advantageous for high-performance capacitors.

There is no need to provide a mechanical constriction to form defined tear-off forces, so that disadvantageous Stromengstellen are avoidable. The combination of contact wire with copper tapes by friction welding and the variable parameters allow the possibility of creating sufficient current-carrying electrical contacts and to ensure reproducible pull-out of the wire relative to the copper foil or the copper strip.

To form the friction stir welding compound, in particular the friction friction spot welding is suitable as a result of extensive experiments.

Preferably, the first connecting element is with a

End face substantially perpendicular to a surface portion of the second connecting element standing connected by the aforementioned friction stir welding.

The attachment of the joining partners takes place so that the surface of the second connecting element, that is the band or

strip-shaped or sheet-like or foil-shaped part is arranged to the front side of the wire and an overlap is provided. The resulting lap joint is then joined by the inserted rotary friction tool, which predominantly dips into the second connecting element. In particular, because of joining partner positioning, a projection of the stiff, wire-shaped, first

Provide connecting element, so that additional material

ready to be heated in the joining zone and to

increase transporting material volume.

In one embodiment, cavities may be provided on the end face of the necessary tool to allow a wire projection via a bore or recess in the sheet-metal joining partner, that is, the second connecting element, and thus protruding Provide material in addition to plasticizing and on the

Forming movement of the tool in the region of the connection zone to transform and with the thin-walled, sheet-like, first

Connecting connecting element. It has surprisingly been found that with the application of the friction stir welding process to form an electrical

Connecting arrangement, this can be realized between two completely different shaped contact elements, without the melting of the base materials or a filler material is required. By positioning the workpieces, that is, the first and second connecting element as well as the local, friction-based energy input, even thin-walled or mechanically low-load components can be joined, without causing a significant deformation outside the actual joining zone. In addition, over the

Process management and the resulting connection surface a required strength range or a specification of the tearing force can be adjusted.

During the actual friction welding process, the rotating friction welding tool acts on the free surface of the second connecting element opposite the end face of the first connecting element.

Finally, the first connection element does not have any current points outside the contact and connection point, as is required in the prior art in order to accomplish a tear-off function.

In a preferred embodiment of the invention, the ratio between the diameter of the first connecting element, that is, of the wire, and the thickness of the second connecting element, that is the band or the film, in the range of 5: 1 to 20: 1.

Preferably, the diameter of the first connecting element is in the range of 1.5 to 3 mm and the thickness of the second connecting element is in the range of 0.1 to 0.5 mm. In the section of the contact and junction points in one

Formation of the invention, the second connecting element to a reduced width. This may be a tapered taper in conjunction with a defined radius of curvature or the formation of a tip.

The invention will be explained in more detail below with reference to embodiments and with reference to figures and photorealistic representations.

Hereby show:

Fig. 1 and Fig. 2 are perspective views of a known

electrical connection arrangement for power capacitors with tear-off function with recognizable ribbon-shaped connection element in the form of a copper foil, large-area solder contact and a wire-shaped conductor with pinch (Fig. 1) and punched (Fig. 2) to form a tear-weakening point, the same time

disadvantageous Stromengstelle leads;

Fig. 3 is a schematic representation of the invention

Forming an electrical connection assembly with Abreißsicherungsfunktion, wherein the contact and connection point is realized by friction stir welding and the Rührreibschweißverbindungsbereich forms the mechanical breakaway with defined pull-off force and high pulse current carrying capacity;

4 is a photorealistic representation of the top view of the contact and connection point, viewed from the wire side, that is, from the side of the first connecting element; Figure 5 is a view similar to that of Figure 4, but from the bottom, that is, from the side on which the Reibschweißwerkzeug acts.

Fig. 6 shows a microsection of the connection point, which

simultaneously represents the actual mechanical breakaway; and

Fig. 7 is a side view and a plan view of

electrical connection arrangement with contact and connection point by friction stir welding realized with exemplary material and design information and the geometry of the second, band-shaped connecting element in the region of the contact and connection point.

Figs. 1 and 2 show a basic construction of an electrical connection assembly with Abreißsicherungsfunktion, as they

For example, in power capacitors is used to prevent that in congestion situations, the risk of exploding the capacitor consists by the breakaway a

electrical network separation is made. The electrical connection arrangement with anti-tearing function shown in FIGS. 1 and 2 is based on a stiff, wire-shaped first connecting element 1 and a thin-walled, strip-like or sheet-like, second connecting element 2.

In the area of a large-area soldering 3, which has been created by crimping one end of the first connecting element 1, is located

Material connection between the first connecting element 1 and the second connecting element 2 before.

To obtain a tear-off is in the first, wire-shaped

Connecting element 1, a pinch 4 or a notch or punched 5 realized. As a result of these material-side effects and changes in the structure of the first connecting element, a destructive process takes place under the action of mechanical force, so that the electrical safety function is provided. The pinch 4 and the punch 5 has at appropriate

Impact current load with the result that there is a local heating due to resistance increase. This in turn gives a

Material weakening with the consequence of changed ductility of the material and thus a no longer reproducible tear-off behavior. In the connection arrangement according to the invention according to FIG. 3, in turn, a first connection element 1 in the form of a wire and a second connection element 2 in the form of a strip are assumed. Both

Connecting elements 1; 2 consist of a copper material.

In one embodiment, the diameter of the wire, that is, the first connecting element 1, at 2 mm and the thickness of the copper strip, that is, the second connecting element 2, is about 0.3 mm. The actual contact and connection point 6 is executed or obtained by friction welding. In this regard, with a suitable tool with clamping of the second connecting element 2 and secured feeding of the first connecting element 1, this is positioned vertically with an end face under projection.

The supernatant is for example 0.1 mm to an adjustment of the plasticized material to the intended rounding bevel to

ensure and reduce the notch effect in the joint zone. The clamping of the band-shaped connecting element 2 is as close as possible to the corresponding tool in order to minimize undesired deformation. As a friction welding joining tool, a tool in a ball-like manner can be easily used, which performs a rotational movement counter to the cutting direction. The speed here reaches from 2000 to 3000 rpm and can go up to the range of 5000 rpm. An exemplary immersion feed is in the range of 10 to 200 mm per minute with an immersion depth of 0.1 to 0.5 mm each after tool execution. Depending on the tool design, the process force also ranges between 150 and 2000 Newton.

The photorealistic illustration of FIG. 4 shows a view comparable to the drawing of FIG. 3 as a view of the connecting parts between the stiff, wire-shaped first connecting element and the band-shaped, thin, second connecting element. At the same time, the preferred geometry in the region of the contact and connection point 6 can be seen. In this regard, there is a conically tapered shape of the second connecting element, wherein a rounding radius is additionally provided. The angle between the resulting quasi triangular legs according to FIGS. 4, 5 and 7 is approximately 60 °.

The view of the joint from below according to FIG. 5 reveals the position of the entry of the tool. This reduction can also be seen in M icrosch I iff the junction of FIG. 6.

The area of this joint represents the mechanical breakaway, which has the necessary pulse current carrying strength, as confirmed by extensive experiments.

Fig. 7 shows an exemplary embodiment of the invention

Breakaway with exemplary dimensioning, which is by no means to be understood limiting.

In this regard, the first connection element 1 is assumed to be tinned copper wire having a diameter of substantially 2 mm. The exemplary length of the wire is 60 mm. The tinned copper wire is connected as shown in FIG. 7 with a free end face via a Reibschweißverbindung with the surface of a copper strip as the second connecting element 2.

The thickness of the copper strip is, for example, 0.3 mm. The width of the copper strip as the second connecting element 2 is chosen according to the embodiment with 10 mm, wherein in the actual region of the contact and connection point 6, the copper strip terminates at an acute angle and has a radius of curvature R2. The angle enclosed by the acute-angled limbs is for example 60 °.

To demonstrate the performance of the advanced electrical connection assembly with anti-tampering function, comparative tests were performed between a classic fuse with 2 mm diameters and a notched or crimped wire design with a 2 mm friction stir welded fuse.

It turned out that, considering the relation of the

Melting Integrals I ² t to the number of shock discharge to the destruction of the fuse solution of the invention is superior to the prior art by a factor of 3 to 4.

Claims

claims

Electrical connection arrangement with tear-off function, in particular for capacitors or the like of electrical or electronic components, wherein the compound consists of a stiff, wire-shaped, first (1) and a thin-walled, band or strip-shaped, sheet-like or foil-shaped, second (2) connecting element and between the first and the second connecting element (1; 2) at a contact and connection point (6) is present,

That's why that is

the contact and connection point (6) is realized by means of friction stir welding and the friction stir welding connection region forms a mechanical breakaway device with a defined pull-off force and high momentum current carrying capacity.

Electrical connection arrangement according to claim 1,

That's why that is

the first connecting element (1) with an end face in the

Substantially perpendicular to a surface portion of the second connecting element (2) is connected standing by friction welding.

Electrical connection arrangement according to claim 2,

That's why that is

during the friction welding process the rotating

Friction welding tool on the end face of the first

Connecting element (1) opposite free surface of the second connecting element (2) acts.

Electrical connection arrangement according to one of

previous claims,

That's why that is

the first connecting element (1) outside the contact and connection point (6) has no Stromengstellen. Electrical connection arrangement according to one of

previous claims,

d a d u rc h e ke n ze ze ch n et that

the ratio between the diameter of the first

Connecting element (1) and the thickness of the second

Connecting element (2) in the range of 5: 1 to 20: 1 is located.

Electrical connection arrangement according to claim 5,

d a d u rc h e ke n ze ze ch n et that

the diameter of the first connecting element (1) in the range of 1.5 to 3 mm and the thickness of the second connecting element (2) is in the range between 0.1 and 0.5 mm.

Electrical connection arrangement according to one of

previous claims,

d a d u rc h e ke n ze ze ch n et that

in the section of the contact and connection point (6), the second connecting element has a reduced area, in particular a reduced width.

Electrical connection arrangement according to one of

previous claims,

d a d u rc h e ke n ze ze ch n et that

the contact and connection point (6)

Friction friction spot welding is realized.