DE102011015219B4 - Solderable electrode and method for producing a solderable electrode - Google Patents

Abstract

Solderable electrode and method for producing a solderable one with a mesh electrode and a strip-shaped solder layer, the strip-shaped solder layer being connected to the mesh electrode. For this purpose, the mesh electrode is pressed from one side with the strip-shaped solder layer.

Description

The present invention relates to a solderable electrode and a method for producing such a solderable electrode.

Such solderable electrodes are versatile. One possible application is the contacting of electrical actuators that are made up of layered materials, for example. In such layer actuators, individual piezoelectric layers are arranged on top of one another and each layer is contacted individually from the sides. When an electrical voltage is applied, the entire length of the electrical actuator changes accordingly.

With such actuators, it is important that the large number of individual piezoelectric layers can be contacted reliably and permanently, even though the entire actuator and also the electrode contacting the actuator are moved and periodically change their length, whereby relative movements between the electrode and the layer actuator may occur.

For these and other applications, solderable electrodes have become known which are provided with a mesh electrode in order to permanently and reliably contact the electrical consumer or the shift actuator via the network. In the manufacturing process, the solderable electrode is soldered to the component to be supplied, such as the shift actuator. In the prior art, it has proven to be costly to provide the required amount of solder in a targeted manner in order to ensure perfect soldering.

From the WO 2004/010 511 A2 An outer electrode is known on a piezoceramic multilayer actuator, the outer electrode consisting of alternating layers of conductive materials and non-conductive materials, and of the two outer layers of conductive materials, one is connected to the basic metallization of the actuator and the other to the supply line for the voltage and the layers of the conductive materials are conductively connected to one another.

With the DE 10 2006 057 178 A1 a solderable network has become known in which the wires woven over a network surface consist of a core which is radially surrounded over the length by a thick layer of tin to provide a homogeneous and evenly distributed amount of solder over the network surface for the soldering process.

This prior art works reliably, but the production is relatively complex overall.

It is therefore the object of the present invention to provide a solderable electrode which offers reliable properties during soldering and which is simpler or cheaper to manufacture.

This object is achieved by a solderable electrode having the features of claim 1. The method according to the invention is the subject matter of claim 11. Preferred configurations and developments of the invention are specified in the subclaims. Further advantages, features and configurations of the invention emerge from the exemplary embodiment.

The solderable electrode according to the invention has a mesh electrode with at least one strip-shaped solder layer.

The strip-shaped solder layer is connected to the mesh electrode. For this purpose, the mesh electrode is pressed with the strip-shaped solder layer from at least one side.

The solderable electrode according to the invention has many advantages. The simple manufacturing process is a significant advantage. First, a mesh electrode can be manufactured in a conventional manner that does not have a supply of solder material to be soldered. Then the finished or at least half-finished mesh electrode is pressed with at least one strip-shaped solder layer. The pressing creates a - at least temporarily - firm bond between the mesh electrode and the strip-shaped solder layer. The bond created is sufficient for further processing of the solderable electrode and for assembly on the product to be soldered. The solderable electrode can then be soldered to the electrical consumer, such as a layer actuator, in a suitable furnace or via another type of heat supply, in order to produce reliable contact with the individual piezoelectric layers of the actuator and to ensure this over the long term.

The strip-shaped solder layer connected to the network electrode represents a solder reservoir which, during the subsequent soldering, ensures reliable and adequate contacting of the product to be contacted. As a result, the following soldering process can be carried out completely without adding any further soldering material.

Another significant advantage of the solderable electrode according to the invention is that that different materials of the mesh electrode and the strip-shaped solder layer can be used. If, on the other hand, a net electrode is to be galvanically coated as a whole, or if the wires used to produce the net electrode are to be galvanically coated with a solder layer beforehand, the problem can arise that certain material combinations cannot be applied galvanically. This means that, depending on the material of the mesh electrode, only certain soldering materials are possible.

In modern soldering processes, the specification of galvanically compatible materials can considerably restrict the choice of material for the mesh electrode and the solder layer. This can result in considerable product, quality and / or price disadvantages, which are avoided with the present invention, since a mechanical connection is created between the mesh electrode and the strip-shaped soldering layer that functions reliably regardless of the materials used.

The shape and structure of the solderable electrode can be selected within extremely wide limits, since basically any external shape can be produced.

In a preferred development, the mesh electrode comprises at least one wire mesh and / or at least one wire mesh and / or at least one wire mesh. The mesh electrode can also comprise a wire fleece or a wire felt or the like.

The mesh electrode is preferably designed to be elastic in at least one dimension and in particular in the longitudinal direction in order, for example, to be able to elastically participate in the corresponding changes in length when a piezoelectric actuator is contacted.

In all of the configurations, the mesh electrode consists at least partially of metallic wires or of wires which have a metallic conductive surface. A wire mesh is particularly preferably used, the wire mesh in particular consisting of metallic wires. The wire mesh can also consist of synthetic or natural material wires which are surrounded by a correspondingly structured metallic layer in order to ensure the necessary conductivity.

The strip-shaped soldering or soldering layer advantageously consists completely or at least predominantly of at least one soldering or soldering material. In particular, the strip-shaped solder layer consists at least essentially completely of at least one solder material. It is also possible for the strip-shaped solder layer to consist of two or more different solder materials.

In principle, all solder materials can be used. Both soft solders and hard solders are preferred. The use of the respective solder material depends on the selected operating environment of the finished solderable electrode and the other requirements.

In particularly preferred configurations, the strip-shaped solder layer is designed as a flat solder foil or as a flat solder plate.

It is also possible, however, for the strip-shaped solder layer to include at least one solder knitted fabric, a solder knitted fabric, a solder braid, a solder fleece, a solder felt or a solder fabric or the like.

Whether the strip-shaped solder layer consists of a solid plate or foil, or whether the strip-shaped solder layer consists of a fabric or the like, is fundamentally irrelevant, provided that the strip-shaped solder layer is structured in such a way that a distribution of the solder layer during the subsequent soldering process is enabled and guaranteed.

The strip-shaped solder layer is preferably connected at least partially and / or at least in sections to the mesh electrode by brushing. The solder layer is placed on the wire mesh and processed with a brush and / or with a tool with bristles and brushed into the wire mesh at least at certain points. As a result, the thin solder layer adapts to the wire mesh and is connected to it so that it adheres reliably to it during the following process steps. The use of an adhesive material is not required. Alternatively, an adhesive material can be used.

It is also possible and preferred to connect the strip-shaped solder layer at least partially to the mesh electrode by a needle operation. For this purpose, the solder layer is placed on the wire mesh. Both layers are then pressed together by pressing needles or needle-like tools onto the solder layer, which locally deform the solder layer and press it into the gaps in the wire mesh. It is also possible that the needles pierce the solder layer and press parts of the solder layer into the wire mesh. The needle tip is adjusted according to the wire mesh and the solder layer. This can e.g. B. pointed, blunt, round, flat, pyramidal, or any other shape.

In preferred developments, the solder layer has a thickness between 10 μm and 150 μm and in particular between 20 μm and 50 μm. Greater or lesser thicknesses are also possible. The choice of the thickness of the solder layer depends essentially on the amount of solder required in the soldering process. In particular, the amount of solder is also influenced by the thickness of the mesh electrode or by its wire diameter and the size of the solderable electrode.

The solderable electrode particularly preferably has a wire mesh as a mesh electrode. The wire diameter of the warp and / or weft wires of the mesh electrode is preferably between 30 μm and 150 μm and in particular between 40 μm and 100 μm. Depending on the application, smaller or larger values are also possible here. For example, mesh electrodes with wire diameters of 300 μm or 500 μm or 1 mm or more are also possible and preferred.

In all configurations it is particularly preferred if the warp wires and the weft wires of the wire mesh extend at an angle to the longitudinal direction of the solderable electrode. The angle between the longitudinal direction and the warp wires and / or the weft wires is preferably between 30 ° and 60 °. However, angles between 15 ° and 75 ° are also possible. In specific embodiments, the angle is 45 °. Warp and weft wires of the wire mesh that are aligned obliquely to the longitudinal direction ensure a high elasticity of the mesh electrode in the longitudinal direction of the solderable electrode. As a result, when used on piezoelectric actuators, a high elasticity of the solderable electrode can be guaranteed, which contributes to a high level of operational reliability.

The mesh electrode and at least one strip-shaped solder layer are preferably calendered with one another. The calendering applies the necessary pressure to connect the mesh electrode to the solder layer at least for further processing so that the probability of failure during subsequent processing and soldering of the solderable electrode is very low or practically zero.

During calendering, the mesh electrode and the strip-shaped solder layer placed on top or below it run together through two rotating rollers that are at a defined distance. The distance between the rotating rollers is dimensioned such that it is less than the thickness of the wire mesh and the solder layer arranged on it. As a result, high pressure is exerted on the grid electrode and the strip-shaped solder layer, which leads to a local deformation of the strip-shaped solder layer and / or the grid electrode. It has been found that this creates a sufficiently strong connection between the strip-shaped solder layer and the mesh electrode.

In all of the configurations, it is possible and preferred that the mesh electrode with the solder layer connected to it is folded over over at least one section. The solder layer can be arranged inside or outside.

It is possible and preferred that at least one electrical connection element is fastened in the folded-over area. In particular, the folding is carried out over the length of at least one connecting section. It is also possible for the mesh electrode to be folded in as a whole. One or more connection electrodes can be located in the folding area.

It is possible for the mesh electrode with the strip-shaped solder layer arranged thereon to be folded in such that the solder layer is completely or at least partially surrounded by the mesh electrode over the folded-in section.

It is also possible for the solder layer to be on the outside of the folded-in mesh electrode. It is also preferred that a solder layer is provided on one side of the mesh electrode and a solder layer on the other side of the mesh electrode, so that the mesh electrode is connected to a solder layer on both sides. This enables a greater distribution of the amount of solder. Accordingly, a thinner, strip-shaped solder layer can be used on both sides.

In the method according to the invention for producing a solderable electrode, a mesh electrode is at least partially covered with at least one strip-shaped solder layer and then the mesh electrode is pressed with the strip-shaped solder layer.

The method according to the invention also has many advantages, since it provides a simple method for producing a solderable electrode with which reliable soldering to electrical loads is possible. The solder reservoir required for soldering is made available on the solderable electrode.

The pressing process can be carried out in a continuous process. But it is also possible that the pressing process is carried out in a discontinuous process. For example, the pressing can also be carried out during a punching process.

It is particularly preferred that the pressing, or at least one pressing, takes place during calendering.

The mesh electrode is preferably folded at least once over at least one section in order to ensure that an electrical connection element is received and contacted.

Further advantages and features of the present invention emerge from the exemplary embodiments, which are explained below with reference to the accompanying figures.

• 1 eine schematische Draufsicht auf eine erfindungsgemäße verlötbare Elektrode;
• 2 eine verlötbare Elektrode mit einem elektrischen Anschluss in einer schematischen Ansicht;
• 3 einen vergrößerten schematischen Querschnitt durch das Anschlussende einer verlötbaren Elektrode;
• 4 einen schematischen Längsschnitt durch ein Ende der verlötbaren Elektrode;
• 5 eine schematische Darstellung des Kalandriervorgangs;
• 6 eine schematisierte Querschnittsdarstellung eines verlötbaren Netzes im vergrößerten Maßstab; und
• 7 einen schematischen Querschnitt durch ein weiteres Ausführungsbeispiel einer erfindungsgemäßen verlötbaren Elektrode.

In the figures show:

• 1 a schematic plan view of a solderable electrode according to the invention;
• 2 a solderable electrode with an electrical connection in a schematic view;
• 3 an enlarged schematic cross section through the connection end of a solderable electrode;
• 4th a schematic longitudinal section through one end of the solderable electrode;
• 5 a schematic representation of the calendering process;
• 6th a schematic cross-sectional view of a solderable network on an enlarged scale; and
• 7th a schematic cross section through a further embodiment of a solderable electrode according to the invention.

With reference to the accompanying figures, an exemplary embodiment of a solderable electrode is described below 1 explained in more detail.

In the 1 The electrode shown comprises a solder layer 3 here as a sheet-like film 9 is executed. The solder plate 11 is here below the mesh electrode 2 arranged. Of course, it is also possible that the solder layer 3 above the mesh electrode 2 is provided. The solder foil shown here as a rectangle 9 and the corresponding rectangular section of the mesh electrode 2 can also have other shapes.

The mesh electrode 2 consists of a wire mesh 6th , which is made of wires 7th and 8th or warp wires 12th and weft wires 13 consists. The wire diameter 18th the weft wires 13 and the wire diameter 17th the warp wires 12th are here in the exemplary embodiment between approximately 40 μm and 150 μm. The exact dimensions depend on the intended application.

In 2 is a schematic plan view of a finished solderable electrode shown. The solderable electrode 1 comprises a wire mesh 6th as a mesh electrode 2 . The wire mesh 6th or the warp wires 12th and the weft wires 13 of the wire mesh 6th point here to the longitudinal direction 15th the solderable electrode 1 an angle 14th which is 45 degrees in the exemplary embodiment.

At the connection section arranged on the left in the exemplary embodiment 16 is a connection element 19th recorded. For secure mounting of the connection element 16 can the connection section 16 be folded over or folded on top of each other in order to securely receive the connection element 19th to guarantee. It is also possible that the mesh electrode 2 the solderable electrode 1 overall with the solder layer 3 is folded down.

3 shows a cross section through the solderable electrode 1 . It is used as a solder foil 9 executed solder layer 3 by pressing with the mesh electrode 2 connected. After the pressing process, the side sections are the mesh electrode 2 been folded down, with a connection element inside 19th can be provided around the solderable electrode 1 to connect to a current or voltage source or a control device or the like.

In the schematic representation according to 3 are the bending edges on the left 20th and 21st drawn, while on the right-hand side both bending edges as a whole with the reference number 36 are provided. At this point it should be noted that the representation of the 3 is a schematic representation. It is possible that only one bending edge is provided on the right and left side. In areas where there is no electrical connection element 19th is provided, for example, is the upper right section 33 with the associated upper right section 23 the mesh electrode regularly directly on the lower portion of the solder layer 34 so that only one bending edge 36 is available. The upper left section 22nd the mesh electrode 2 then lies with the upper left section 32 the solder layer 3 right on the lower section 24 the mesh electrode 2 on.

The gaps between the individual components shown in the figures only serve to clarify the principle and are generally not present in a real embodiment in order to ensure that the individual components are appropriately fixed to one another.

4th shows a longitudinal cross section in the area of the connection section 16 in which the electrical connection element 19th not between the individual layers of the solderable electrode 1 , but outside z. B. spotted is provided. Inside lies between the layers of the folded mesh electrode 2 one layer of solder foil each 9 . The Connection element 19th could also be added inside between the individual layers.

While the thick 10 the solder foil 9 typically in the range from 20 to 70 µm, the thickness is 27 one layer of the mesh electrode 2 here between 50 µm and 150 µm. The total thickness 31 the finished solderable electrode adds up accordingly. In the areas where an electrical connection element 19th is provided, the thickness increases 31 correspondingly strong, while it is correspondingly lower in the other sections.

5 shows the calendering device 28 , with which the solder layer here 3 with the mesh electrode 2 is pressed. The mesh electrode 2 with the solder layer placed on it 3 has an initial thickness before calendering 35 which is greater than the distance between the two rollers 29 and 30th of the calendering device 28 . When passing through the calendering device 28 becomes the composite of mesh electrode 2 and solder layer 3 generated and amplified. Both the thickness of the solder layer 3 as well as the thickness of the mesh electrode 2 be reduced until the total thickness 31 adjusts. The massive pressure on the mesh electrode and the solder layer creates a firm bond between the mesh electrode and the solder layer. This can also be done by folding over the mesh electrode 2 be reinforced.

During calendering, the total thickness is usually reduced by between 10% and 60% depending on the parameters set. Pressings greater than 20% are preferred. In a specific embodiment, a good result was achieved with a reduction in thickness between 30% and 40%.

In 6th Figure 3 is, in a schematic manner, an enlarged cross-section of the finished solderable electrode 1 shown. Some warp wires are shown 12th and a weft wire 13 . By calendering the layer of mesh electrode 2 and solder layer 3 have attached themselves to the tips of the weft wires13 (and to the tips of the warp wires, which are not visible here 12th ) Flats 25th the mesh electrode and at the corresponding points of the solder layer 3 have corresponding flattenings 26th the solder layer 3 surrender.

In the example shown is the solder layer 3 on the website 4th of the wire mesh 6th provided while on the side 5 no solder layer is present. However, it is also possible to have a solder layer on each side of the mesh electrode 3 to be provided. The fat 10 the respectively applied solder layers can be correspondingly smaller in order to still ensure reliable soldering. As a rule, the thickness of the solder layers and thus the amount of solder material are adapted to the soldering process.

7th shows an embodiment in which the mesh electrode 2 on a correspondingly large layer of solder 9 was placed and both together along the bending edges 20th and 36 were folded over. The solder layer 9 is located outside here, while the mesh electrode 2 completely from the solder layer 9 is surrounded. Following the bending or folding process, the mesh electrode 2 together with the solder layer 9 calendered. This creates a surface such as that shown in 6th is shown. Overall, a solid connection is created that holds both components securely until the soldering process.

Overall, the invention according to the invention provides a simple method and a solderable electrode that is easy to manufacture, with which, for example, electrical actuators can be reliably and permanently controlled.

List of reference symbols

1

solderable electrode

2

Mesh electrode

3

Solder layer

4th

page

5

page

6th

Wire mesh

7th

wire

8th

wire

9

Solder foil

10

thickness

11

Solder plate

12

Warp wire

13

Weft wire

14th

angle

15th

Longitudinal direction

16

Connection section

17th

Wire diameter

18th

Wire diameter

19th

Connection element

20th

Bending edge

21st

Bending edge

22nd

upper left section of the mesh electrode

23

upper right section of the mesh electrode

24

lower section of the mesh electrode

25th

Flattening of the mesh electrode

26th

Flattening of the solder layer

27

Mesh electrode thickness

28

Calendering device

29

roller

30th

roller

31

Total thickness, final thickness

32

upper left section of the solder layer

33

upper right section of the solder layer

34

lower section of the solder layer

35

Thickness before calendering

36

Bending edge

Claims (12)

Solderable electrode (1) with a mesh electrode (2) and at least one strip-shaped solder layer (3), the strip-shaped solder layer (3) being at least temporarily connected to the mesh electrode (2), including the mesh electrode (2) from at least one side (4 , 5) is pressed from with the strip-shaped solder layer (3). Solderable electrode (1) according to Claim 1 , wherein the mesh electrode (2) comprises at least one wire mesh (6) and / or at least one wire mesh and / or at least one wire mesh and in particular at least partially consists of metallic wires (7, 8) and / or wherein the strip-shaped solder layer (3) at least comprises a solder knitted fabric, a solder knitted fabric, a solder braid, a solder felt or a solder fabric. Solderable electrode (1) according to one of the preceding claims, wherein the strip-shaped solder layer (3) consists at least predominantly of at least one solder material, and / or wherein the strip-shaped solder layer (3) as a flat solder foil (9) and in particular as a flat solder plate (11) is trained. Solderable electrode (1) according to one of the preceding claims, wherein the strip-shaped solder layer (3) is at least partially connected to the mesh electrode (2) by brushing. Solderable electrode (1) according to one of the preceding claims, wherein the strip-shaped solder layer (3) is at least partially connected to the mesh electrode (2) by a needle operation. Solderable electrode (1) according to one of the preceding claims, the solder layer (3) having a thickness (10) between 10 µm and 150 µm and in particular between 20 µm and 50 µm. Solderable electrode (1) according to one of the preceding claims, wherein at least one wire diameter (17, 18) of the warp and / or weft wires (12, 13) of the mesh electrode (2) is between 30 µm and 150 µm and in particular between 40 µm and 100 µm µm. Solderable electrode (1) according to one of the preceding claims, wherein the warp wires (12) and the weft wires (13) of the wire mesh (6) extend at an angle (14) to the longitudinal direction (15), the angle (14) in particular between 30 ° and 60 °. Solderable electrode (1) according to one of the preceding claims, wherein the mesh electrode (2) and at least one strip-shaped solder layer (3) are calendered with one another. Solderable electrode (1) according to one of the preceding claims, wherein the mesh electrode (2) with the solder layer (3) connected to it is folded over over at least one section (15) and / or wherein the mesh electrode (2) with the solder layer (3) connected therewith ) is folded over over at least one connection section (16), an electrical connection element (19) also being folded in. Method for producing a solderable electrode (1), wherein a mesh electrode (2) is covered with at least one strip-shaped solder layer (3) and wherein the mesh electrode (2) is then pressed with the strip-shaped solder layer (3). Method according to the preceding claim, wherein the mesh electrode (2) is covered on both sides (4, 5) with at least one strip-shaped solder layer (3) and then pressed and / or wherein the mesh electrode (2) is folded at least once over at least one section .

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