DE102016211159A1 - Condenser dielectric material, film winding capacitor and process for its production - Google Patents

Abstract

The invention relates to a capacitor dielectric material for an electrical capacitor (1), comprising a ceramic material (12) and a matrix material (13), in which the ceramic material (12) is contained, wherein the capacitor dielectric material is liquefied by melting, so that it liquifies to a Capacitor electrode can be applied. The invention also relates to a film winding capacitor comprising such a capacitor dielectric material and to a method for producing such a film winding capacitor (1).

Description

The invention relates to a capacitor dielectric material, a film winding capacitor with such a capacitor dielectric material and a method for producing the film winding capacitor.

Are known wound film capacitors (= film winding capacitors) based on a coated polymer material, such as PET or PP. Metallically coated polymer films are hereby wound overlapping laterally and then provided with electrical contacts. Thereafter, the winding can be introduced into a capacitor housing. The polymer material serves as a capacitor dielectric material, ie as the dielectric of the capacitor. Such capacitors are very inexpensive to manufacture and are used, for example, for DC link capacitors in power electronics modules, such as in inverters. Their ampacity is mediocre to high according to the thickness of the metallization. The temperature resistance of PET or PP films is usually a maximum of 105 ° C. Higher temperatures can be achieved with other polymer materials, but then the costs increase very much and also technical compromises go along with it.

In order to increase the capacity density and at the same time the temperature resistance, a change of the dielectric material is required. Ceramics could offer a good compromise here. However, the manufacturing methods known today for capacitors with ceramic dielectric materials are expensive. Ceramic capacitors are built flat and stacked layer by layer, with alternating ceramic insulator material and electrical conductors being applied alternately. The thinner the layers, the higher the achievable capacity density. A ceramic multilayer capacitor thus usually consists of many individual capacitors, which are stacked on top of each other and are contacted via connection surfaces together in parallel. Of the manufacturing methods for ceramic capacitors known today, multilayer technology (MLCC) is the most interesting in terms of the most important comparison variable: capacitance density per volume at a given voltage.

The batch process required for this, however, is time-consuming, error-prone and expensive. Missing self-healing properties mean that a single fault, such as a short circuit, can lead to failure of the entire capacitor. Therefore, only relatively small capacitors up to several hundred nF are manufactured in this way. The production of large capacitors down to the 1 mF range has hitherto generally been prohibited for technical and economic reasons.

From the US 5,140,498 A It is known to coat metal strips for wound capacitors on both sides with a metal oxide. For this purpose, the metal oxide is first brought into solution with an alcoholate and thus liquefied. The metal strip is coated with the metal oxide-alcoholate solution, for example by spraying or dipping. Subsequent to the coating process, the organic components of the applied metal oxide alkoxide layer are removed by heating or burnout. Back on the metal strip thus remains the metal oxide. By subsequently winding the metal strip, a wound capacitor is produced in which the metal oxide remaining after heating serves as a capacitor dielectric material. The metal oxide-alcoholate solution used for the coating itself therefore does not serve as a capacitor dielectric material.

A disadvantage of this production method is that an extra step for expelling the organic components from the applied metal oxide-alcoholate solution is required.

The object of the invention is to provide a capacitor dielectric material which allows a simple production of a film winding capacitor, as well as to provide a film winding capacitor produced in a simpler way and a simple method for producing a film winding capacitor.

This task is solved by the features of the skin spokes. Preferred embodiments are the dependent claims. Accordingly, there are proposed: a capacitor dielectric material, a film winding capacitor with such a capacitor dielectric material and a method for producing such a film winding capacitor with the capacitor dielectric material.

The proposed capacitor dielectric material is designed for an electrical capacitor. He serves as a dielectric there. For this purpose it is arranged in the capacitor between two electrodes. The proposed capacitor dielectric material has a ceramic material as a dielectric as well as a matrix material in which the ceramic material is contained. In particular, the ceramic material is dispersed or dissolved in the matrix material. In particular, the capacitor dielectric material consists of precisely this one ceramic material and this one matrix material. It is envisaged that the capacitor dielectric material by melting is liquefiable, so that it is liquefied on a capacitor electrode can be applied.

For coating a capacitor electrode, the state of aggregation of the capacitor dielectric material is therefore initially changed to liquid. For this purpose, the capacitor dielectric material is heated. After application to the electrode, the material is converted back to its solid state by cooling. The cooling can be done independently or with the aid of an extra cooling device, such as a cooling unit or a cooling fan. Immediately after solidifying the capacitor dielectric material, a capacitor may then be wound by winding the coated electrode. In particular, a capacitor electrode made of metal foil can be coated with the capacitor dielectric material thus melted.

In particular, the matrix material can be liquefied by the melting. The matrix material is accordingly in particular a thermoplastic material. The ceramic material contained in the matrix material may continue to be solid in the molten state of the matrix material. In other words, the melting point of the matrix material is then preferably below the melting point of the ceramic material, in particular clearly below it. For example, the difference between the melting points of the ceramic material and the matrix material is more than 500 Kelvin, in particular more than 1000 Kelvin.

Preferably, the melting point of the matrix material is above the maximum operating temperature of a conventional electrical capacitor (150-200 ° C). The capacitor dielectric material is thus preferably still at least up to a maximum capacitor operating temperature or up to a temperature of 200 ° C fixed. The melting point of the ceramic material can be correspondingly higher.

The matrix material is preferably non-evaporating at least up to a maximum condenser operating temperature or up to a temperature of 200 ° C. Thus, up to this temperature substantially no components, such as solvents or plasticizers, etc. evaporate from the matrix material. Up to this temperature, therefore, no degradation or change in the material composition of the matrix material takes place. Since the matrix material contains the ceramic material and the ceramic material is in particular thermally more resistant than the matrix material, no degradation of the capacitor dielectric material up to this point takes place per se.

To produce a capacitor with the capacitor dielectric material, this material is thus preferably first heated above the melting point of the matrix material, but still below the melting point of the ceramic material. For example, to a temperature greater than 200 ° C and less than 500 ° C. Thus, the liquefaction of the matrix material and thus of the capacitor dielectric material occurs. The condensate dielectric material thus liquefied by melting can then be applied to a capacitor electrode. Subsequently, the capacitor dielectric material is cooled, for example to an ambient or room temperature (20-25 ° C), at least until it solidifies. Subsequently, a wound capacitor can be wound with the thus coated electrode.

The cooling of the applied capacitor dielectric material before further processing, for example before winding to the capacitor, does not have to be completely carried out at ambient temperature. Thus, the cooling to a certain processing temperature, which is above the ambient temperature or above the subsequent operating temperature of the capacitor produced therewith (ie in particular greater than 200 ° C), take place. Although the capacitor dielectric material or the matrix material already has a certain strength at this processing temperature, it is not completely solidified. He thus still has an increased flexibility, by which he is well plastically deformable and thus easy weiterverarbeitbar. Thus, in particular, a winding process for producing a wound capacitor with the capacitor dielectric material can be facilitated.

The proposed capacitor dielectric material does not require extra burn-out or otherwise expulsion of the matrix material after coating on an electrode. The matrix material thus forms a part of the dielectric in the finished capacitor together with the ceramic material. In this case, the dielectric properties of the ceramic material can be far superior to those of the matrix material. For example, the relative permittivity of the matrix material may be significantly lower than that of the ceramic material.

The electrode to which the capacitor dielectric material is applied is in particular a foil. This is preferably a (thin) metal foil, such as copper or aluminum foil. The film is designed in particular as a sheet, ie as a solid metal foil. The film itself then consists in particular of a single homogeneous metal layer.

The ceramic material is preferably finely divided, that is, as a dispersed powder in the matrix material. Alternatively, the ceramic material may be dissolved in the matrix material. In the latter case, the matrix material thus forms a solvent for the ceramic material. It has been found that a mean (ie average) grain size of the ceramic material introduced into the matrix material should be at most 100 nm. Accordingly, the average particle size of the ceramic material is particularly preferably less than 100 nm. For this purpose, the ceramic material is in particular finely ground.

The matrix material is preferably organic. It is thus based in particular on carbon chains. However, it is also possible that he is based on Si chains. The matrix material is preferably an organic thermoplastic. Preferably, the matrix material of polytetrafluoroethylene (= PTFE) and / or syndiotactic polystyrene (= SPS) or includes these (s). Thus, the matrix material may in particular consist of or contain one of these two substances, or it may consist of or comprise a mixture of these two substances. These materials have proven to be a particularly suitable matrix material.

The ceramic material is particularly preferably made of lead zirconate titanate (= PZT) or includes this. Also, this material has been found to be particularly suitable for this. Preferably, a capacitor dielectric material is used in which the matrix material consists of PTFE and / or SPS and the ceramic material of PZT.

The proposed film winding capacitor has a first electrically conductive film as a first capacitor electrode and a second electrically conductive film as a second capacitor electrode. The first and / or second film is or are coated with the proposed capacitor dielectric material and wound together. By eliminating expulsion of the matrix material from the capacitor dielectric material, such a capacitor can be easily manufactured.

Preferably, exactly one or exactly two layers of the capacitor dielectric material are arranged between a winding layer of the first film and a winding layer of the second film. It can be coated on both sides only one of the two films with the capacitor dielectric material before the two films are rolled up together. Alternatively, both films can be coated on one side only with the capacitor dielectric material. As a result, exactly one layer of the capacitor dielectric material is formed between the winding layers.

It is also possible for both films to be coated on both sides with the capacitor dielectric material before the two films are rolled up together. As a result, exactly two layers of capacitor dielectric material are formed between the winding layers. If two layers of capacitor dielectric material are provided, the thicknesses of the individual layers may be reduced, which may ultimately result in the same thickness of dielectric between the winding layers as in a single layer.

As explained above, the film is preferably a metal foil such as a (thin) metal sheet. In particular, the film of aluminum or copper (alloys thereof or with one of these metals as the main component are included), so an aluminum or copper foil. Alternatively, it may be a metal-coated, for example steamed, foil. The foil serves as the electrode of the capacitor. Accordingly, their electrical resistance should be low, which is the case with aluminum or copper foil.

The proposed manufacturing method is used to produce the proposed film winding capacitor or a film capacitor with the proposed capacitor dielectric material.

As part of the proposed method, the capacitor dielectric material is liquefied by melting in a first step. In particular, the matrix material is liquefied by melting. The ceramic material can then continue to be solid, but finely distributed in the matrix material.

In a second step following the first step, the first and / or second film is coated with the thus condensed capacitor dielectric material. Depending on whether one or two layers of capacitor dielectric material are provided between the later winding layers of the capacitor, only one or both films (one-sided or two-sided) are coated. The coating preferably takes place in such a way that the capacitor dielectric material is applied to the respective film by a spraying method or a dipping method. Optionally, several such coating operations take place until the desired layer thickness of capacitor dielectric material is reached.

In a subsequent third step, the coated capacitor dielectric material is cooled so that it solidifies. As explained, he does not need to be completely frozen in this case. Preferably, it further has a processing temperature which is a certain (increased) Flexibility for further processing, in particular the subsequent winding allowed.

In a subsequent fourth step, the film capacitor is wound by winding the films together. In this case, therefore, the two films are wound together with the coated capacitor dielectric material. This results in a structure of the capacitor, in which a winding layer of the first film in cross-section peel off through a winding layer of the second film with the interposed dielectric material.

Baking or otherwise expelling the matrix material or ingredients thereof is not required in the proposed manufacturing process. Such a step is therefore deliberately not intended. The proposed method is thus energy efficient and inexpensive feasible.

In particular, the application of the capacitor dielectric material to the film (s) takes place by spraying with at least one nozzle. In this case, the liquefaction of the dielectric material can be effected in particular in that the nozzle is heated. The capacitor dielectric material is then fed in solid form to the nozzle, heated therein and thereby liquefied. Through a nozzle opening of the liquefied material is then ejected in the direction of the film (s) and this coated. As an alternative to this, the capacitor dielectric material can also be liquefied and fed to the nozzle by melting. Then this serves only for spraying the material and not in addition to liquefaction.

Particularly preferably, the layer thickness of the capacitor dielectric material applied to the first and / or second film is sufficiently low that the heat discharge from the capacitor dielectric material during coating on this film leads to the solidification of the capacitor dielectric material. The advantage of this is that the capacitor can be wound immediately after coating. For this purpose, the film has a lower temperature shortly before the coating step than the capacitor dielectric material during coating or application to the film.

The film can be cooled down extra. Normally, however, it is sufficient if the film has room temperature. Due to the usually good thermal conductivity of the film, in particular if it is designed as a metal foil, heat is dissipated correspondingly quickly from the capacitor dielectric material. Thus, there is a rapid dissipation of heat and solidification of the dielectric material on the film.

The required temperature difference between the film and the capacitor dielectric material can easily be determined on the one hand based on the solidification temperature or the melting point and the heat capacity of the capacitor dielectric material on the one hand and the heat capacity of the film to be coated.

In the proposed method, a (first) layer of the capacitor dielectric material (= dielectric layer) is preferably brought between two films as electrodes before they are wound up into the wound capacitor. The two films each have a first contact side and a second contact side. The two films are combined with their first contact side and optionally pressed together. The (first) dielectric layer is then introduced between the first contact sides of the films when the films are brought together, in particular sprayed. The (first) dielectric layer is thus applied to the films while these are combined with their first contact sides. The dielectric layer is particularly homogeneous, d. H. she does not show any layering herself.

The films are in particular the same width. In particular, they are brought together with an offset so that the end faces of the capacitor winding formed therefrom can each be electrically contacted with one of the foils. Because of the offset, namely, the first film protrudes from one of the front sides and the second film protrudes from the opposite other end side. These end faces are then easily and independently electrically contacted.

Preferably, the films are wound with the interposed first dielectric layer to form a capacitor winding. In this case, a second dielectric layer made of the proposed capacitor dielectric material is introduced as a dielectric between the second contact sides of the films which abut one another during winding. The introduction of the second dielectric layer between the second contact sides then takes place during winding of the capacitor winding. The capacitor winding forms after contacting the films or electrodes a film winding capacitor.

In the following, the invention is explained in more detail by figures, from which further preferred embodiments and features of the invention can be removed. The figures show in schematic representation:

1 and 1a a film winding capacitor,

2 a first production process for a film winding capacitor,

3 a second production process for a film winding capacitor,

4 a third production process for a film winding capacitor,

5 a fourth manufacturing method for a film winding capacitor,

6 a capacitor dielectric material.

In the figures, identical or at least functionally identical elements (components etc.) are provided with the same reference numerals. In the 2 to 7 the directions of rotation of the respective rolls / coils are indicated by arrows.

1 and 1a shows a built up of a capacitor winding film winding capacitor 1 , 1 shows the capacitor 1 with fanned layers, while 1a a cross section through the capacitor 1 out 1 shows, wherein also the layers contained therein are visible. A longitudinal axis of the capacitor winding is denoted by L. The end faces of the capacitor winding or capacitor 1 are located at its axial ends or end faces with respect to the longitudinal axis L.

The capacitor 1 is on its faces, each with an electrically conductive termination 2 Mistake. These are each electrical with a connection 3 contacted. The graduations 2 contact each one wound up as an electrode used foils 4 . 5 electric. At the graduations 2 it may, for example, each be an electrically conductive metal plate or metal coating.

The slides 4 . 5 are preferably each formed by a metal foil, in particular a thin metal sheet made of solid metal. Between the slides 4 . 5 is exactly one particular homogeneous, ie in particular not further layered, dielectric layer 6 . 7 provided as a dielectric. The dielectric layers 6 . 7 consist of a capacitor dielectric material.

The slides 4 . 5 and the dielectric layers 6 . 7 are offset from each other or wound, as in 1a visible, noticeable. This is ever one of the slides 4 . 5 on each of the front sides of the coil 1 and can easily with the associated degree 2 be contacted electrically.

The slides 4 . 5 each have a first and a second contact surfaces 4a . 5a and 4b . 5b on. The first dielectric layer 6 is between the first contact surfaces 4a . 5a arranged. The second dielectric layer 7 is between the second contact surfaces 4b . 5b arranged. As a result, the first contact surfaces are in the winding 4a . 5a directed to each other and the second contact surfaces 4b . 5b directed towards each other. Through the dielectric layers 6 . 7 are in the wrap the slides 4 . 5 electrically isolated from each other.

The dielectric layers 6 . 7 are formed, for example, by the fact that capacitor dielectric material when merging the contact surfaces 4a With 5a and the contact surfaces 4b With 5b between these contact surfaces 4a and 5a . 4b and 5b is introduced or sprayed. Preferred methods for this are the 2 to 6 removable. Alternatively, the dielectric layers 6 . 7 be formed by one or both of the films 4 . 5 be coated in a dipping process with capacitor dielectric material. A preferred method for this is the 7 removable.

The capacitor dielectric material for the dielectric layers 6 . 7 consists of a ceramic material and a matrix material in which the ceramic material is contained, in particular dispersed therein or dissolved therein. It is liquefiable by melting, ie heating. Thus, it is liquefied on a capacitor electrode, in the present case, the films 4 . 5 , orderable. The matrix material is preferably made of PTFE and / or SPS. The ceramic material is preferably made of PZT. A preferred capacitor dielectric material is, for example, in 6 shown.

2 shows a method of manufacturing a capacitor winding 1 or a wound capacitor, such as the one from 1 , Here, a first dielectric layer 6 as a dielectric between two films 4 . 5 introduced as electrodes before they are wound up. The slides 4 . 5 each have a first contact page 4a . 5a and a second contact page 4b . 5b on. The two slides 4 . 5 be with their first contact pages 4a . 5a merged. It is now envisaged that the first dielectric layer 6 between the first contact pages 4a . 5a is introduced while the slides 4 . 5 with these contact pages 4a . 5a be merged.

These are the two slides 4 . 5 initially as roles 4c . 5c , For example, transport wheels provided. On each of these is one of the slides 4 . 5 wound. These roles 4c . 5c are pressed against each other and are unrolled together. As in 2 is apparent, the directions of rotation of the roll 4c . 5c thus contrary. When unrolling the slides 4 . 5 from the roles 4c . 5c These become their first contact pages 4a . 5a towards a roll-off side (in 2 right of the rollers 4c . 5c ) merged. The first dielectric layer 6 This is between the first contact pages 4a . 5a the slides 4 . 5 on the opposite side of the rollers to the roll-off side 4c . 5c (in 2 to the left of the rollers 4c . 5c ), ie in the 2 marked area A. This introduction thus takes place during the merging of the contact pages 4a . 5a ,

In detail, the introduction or forming of the first ceramic layer 6 according to 2 in that a capacitor dielectric material for the first dielectric layer 6 between the first contact pages 4a . 5a the slides 4 . 5 is sprayed while the slides 4 . 5 with these first contact pages 4a . 5a be merged. By compressing the rollers 4c . 5c The sprayed capacitor dielectric material can also be compressed the same.

The spraying of the capacitor dielectric material is effected by at least one nozzle 8th , For this purpose, the material is liquefied by melting. The liquefaction can be done by the nozzle 8th is heated. The capacitor dielectric material is in solid form of the nozzle 8th supplied, heated therein and thereby liquefied. Through a nozzle opening of the nozzle 8th The liquefied dielectric material is then in the direction of the films 4 . 5 pushed out. Alternatively, the capacitor dielectric material can already be liquefied by melting the nozzle 8th be supplied. Then this serves only for the corresponding spraying of the dielectric material.

The nozzle 8th By way of example, the spray jet is aligned in the gap between the two films 4 . 5 is directed, ie a main axis of the spray is directed to the gap. The spray density is with the rolling or web speed of the films 4 . 5 so attuned that the thus formed dielectric layer 6 receives the required electrical properties. The thickness of the dielectric layer thus formed 6 is in particular about 1 micron. So that the dielectric layer 6 on the slides 4 . 5 adheres or the capacitor dielectric material during spraying on the films 4 . 5 is attracted, the spray and the films 4 . 5 be charged differently magnetically or electrically.

The solidification of the capacitor dielectric material takes place sufficiently fast that films 4 . 5 can be wound after the coating with the capacitor dielectric material. In particular, take the slides 4 . 5 a sufficiently large amount of heat, so that solidification sets in immediately. The temperatures of the films 4 . 5 and the sprayed Kondensatordielektrikumwerkstoffs are matched accordingly.

After merging the slides 4 . 5 and introducing / forming the first dielectric layer 6 become the slides 4 . 5 with the interposed first dielectric layer 6 to the capacitor winding 1 wound. This automatically puts the second contact pages 4b . 5b the slides 4 . 5 to each other, ie they are then merged, see in 2 marked area B.

The second dielectric layer 7 is according to 2 just then introduced or formed while the second contact pages 4b . 5b when winding up the capacitor winding 1 contiguous or merged, ie in the in 2 This is done according to 2 by spraying the capacitor dielectric material by means of at least one (second) nozzle 8th , In this case also apply with regard to the spraying of the first dielectric layer 6 made statements.

According to 2 Optionally, at least one support roller 9 be provided, against the winding 1 pressed. This ensures a compression of the second dielectric layer 7 and optionally also an additional compression of the first ceramic layer 6 , There may also be other support rollers 9 be provided, in particular to the films 4 . 5 with the interposed first dielectric layer 6 tighten and / or in the direction of the roll 1 to deflect (see, for example, support rollers 9 in 3 ).

It is preferably provided that the capacitor dielectric material after application to the films 4 . 5 still has a certain temperature and thus flexibility, so that the winding and compacting can take place easily.

3 shows a modification of the manufacturing method according to 1 , In contrast to 2 are according to 3 the roles 4a . 5c the slides 4 . 5 spaced apart. They are therefore spaced from each other unrolled and are not compressed. Merging the slides 4 . 5 with her first contact page 4a . 5a takes place by means of pressed against each other support rollers 9a , Accordingly, then the first dielectric layer 6 between the first contact pages 4a . 5a on the roll-off side (in 2 right of the support rollers 9a ) opposite side of the support rollers 9b brought in.

Analogous to the method according to 2 are also in the process after 3 the dielectric layers 6 . 7 by spraying on the two merged contact sides 4a and 5a . 4b and 5b generated. In this regard, the procedure according to 2 made statements therefore also apply 3 to.

According to the in 4 The manufacturing process shown, the application of the second dielectric layer 7 also after the introduction of the first dielectric layers 6 between the slides 4 . 5 , but before winding to wrap 1 , For this purpose, the second dielectric layer 7 Applied by capacitor dielectric material of at least one support rollers 9 to this second contact page 4b . 5b is applied, preferably it is by means of pressed against each other support rollers 9 pressed against it. For this purpose, capacitor dielectric material is applied to the second contact side 5b sprayed. The film thus formed is replaced by the support roller (s) 9 to the second contact page 4b . 5b targeted pressed. It may alternatively be provided that the capacitor dielectric material on the second contact side 5b is sprayed on without an extra application by a support roller (s) 9 he follows.

According to the in 5 The manufacturing method shown applying the dielectric layers is applied to the films 4 . 5 by a dipping process. These are the slides 4 . 5 each by a dip 10 . 11 guided. These contain in each case molten, ie liquefied, capacitor dielectric material. This lies on both sides of the dipped in it foil 4 . 5 and coat them by. After performing the dip coating, a cooling stretch of the coated films 4 . 5 to go through. In the simplest case, this may be a transport path on, in particular purified, ambient air. Alternatively, it can also be a route through an active cooling device, for example a cooling unit, which cools the ambient air and / or a ventilation device, the ambient air via the films 4 . 5 blows. As a cooling medium, instead of ambient air and another cooling fluid can be used. After sufficient cooling, the co-winding of the films takes place 4 . 5 to the wrap 1 , In 5 is an example of the cooling path as a box between the winding 1 and the dipping baths 10 . 10 located.

It is noted that as an alternative to the embodiment of 5 also only one of the slides 4 . 5 can be coated on both sides in the dipping process with capacitor dielectric material. In this case, only one of the immersion baths 10 . 11 intended. Between the individual winding layers of the films 4 . 5 then there is exactly one dielectric layer. When dip coating both films 4 . 5 according to 5 There are always exactly two dielectric layers between the winding layers of the films 4 . 5 , However, these can then each be made thinner, resulting in the end effect the same layer thickness of dielectric between the films 4 . 5 can exist, as in the coating of only one of the films 4 . 5 ,

The layer thickness of the dielectric layers in the dip coating is simply due to the viscosity of the tachy baths 10 . 11 adjustable melted capacitor dielectric material. As a rule, the more viscous, the thicker the layer is. For a thermoplastic capacitor dielectric material, the viscosity is dependent on its temperature. Thus, by adjusting the temperature of the material in the immersion baths 10 . 11 directly and simply the layer thickness of the dielectric layers on the films 4 . 5 adjustable.

The slides 4 . 5 be according to the 2 to 5 finally with the dielectric layers 6 . 7 to the capacitor winding 1 wound. Later, the front ends of the capacitor winding 1 with the degrees 2 Provide these and electrically with the terminals 3 contacted. The production process shown requires no sintering process for sintering the dielectric layers 6 . 7 or a burnout process to remove solvent or other ingredients from the dielectric layers 6 . 7 be performed. It is noted that in addition to those in the 2 to 5 Combinations thereof are also possible, in particular when dielectric layers of different capacitor dielectric materials are introduced into the winding 1 should be introduced.

6 shows a section through a capacitor dielectric material, such as a dielectric layer in an electrical capacitor. As 6 it can be seen, the material consists of finely divided grains 12 a ceramic material and one of the grains 12 embedding matrix material 13 , The ceramic material 12 is therefore in the matrix material 13 dispersed. By melting the matrix material 13 the entire capacitor dielectric material is liquefied, wherein the ceramic material or the grains 12 to be firm in itself. Thereby, the capacitor dielectric material can be easily applied to a capacitor electrode such as a metal foil.

How to 1 and 1a already explained is the matrix material 13 preferably PTFE or SPS or a mixture of these two. The ceramic material is preferably made of PZT. The ceramic material is in particular ground, in particular the mean grain size is at most 100 nm. When using a such capacitor dielectric material in a capacitor, the matrix material remains 13 in the condenser. He is therefore not burned out or otherwise expelled. It thus contributes to the dielectricity of the dielectric layer produced therefrom.

LIST OF REFERENCE NUMBERS

1

Film winding capacitor, capacitor winding

2

graduation

3

Electrical connection

4

foil

4a, 4b

Contact

4c

Roll, transport role

5

foil

5a, 5b

Contact

5c

Roll, transport role

6

ceramic layer

7

ceramic layer

8th

jet

9, 9a

supporting role

10

dip

11

dip

12

Grains of ceramic material

13

Matrix material

A, B

Area

L

longitudinal axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5140498 A [0005]

Claims (12)

Condensate dielectric material for an electrical capacitor ( 1 ), with a ceramic material ( 12 ) and with a matrix material ( 13 ), in which the ceramic material ( 12 ), in particular dispersed or dissolved, characterized in that the capacitor dielectric material is liquefiable by melting, so that it is liquefied on a capacitor electrode can be applied. The capacitor dielectric material of claim 1, wherein it is solid at least up to a maximum capacitor operating temperature or up to a temperature of 200 ° C. A capacitor dielectric material according to claim 1 or 2, wherein the matrix material is non-evaporating at least up to a maximum capacitor operating temperature or up to a temperature of 200 ° C. Condensate dielectric material according to one of the preceding claims, wherein the matrix material ( 12 ) is organic. A capacitor dielectric material according to claim 4, wherein the matrix material ( 12 ) Polytetrafluoroethylene and / or syndiotactic polystyrene is or has. Condensate dielectric material according to one of the preceding claims, wherein the ceramic material ( 13 ) Is lead zirconate titanate or has. Condensate dielectric material according to one of the preceding claims, wherein the ceramic material ( 13 ) has a mean particle size of not more than 100 nm. Film winding capacitor ( 1 ) with a first electrically conductive film ( 4 ) as the first electrode and a second electrically conductive film ( 5 ) as a second electrode, wherein the first and / or second film ( 4 . 5 ) are coated with a capacitor dielectric material and wound together, characterized in that the capacitor dielectric material is designed according to one of the preceding claims. Film winding capacitor ( 1 ) according to claim 8, wherein between a winding layer of the first film ( 4 ) and a winding layer of the second film ( 5 ) exactly one or exactly two layers of the capacitor dielectric material are arranged. Method for producing a film winding capacitor ( 1 ) according to claim 8 or 9, wherein in a first step, the capacitor dielectric material is liquefied by melting, and in a subsequent second step, the first and / or second film ( 4 . 5 ) is coated with the thus condensed capacitor dielectric material, and in a subsequent third step, the coated capacitor dielectric material is cooled so that it solidifies, and in a subsequent fourth step of the film capacitor ( 1 ) by co-winding the films ( 4 . 5 ) is wound. Method according to claim 10, wherein the first and / or second film ( 4 . 5 ) is coated with the capacitor dielectric material by a spraying method or a dipping method. The method of claim 11, wherein the layer thickness of the first and / or second film ( 4 . 5 ) applied capacitor material is sufficiently low that takes place during coating heat dissipation of the capacitor dielectric material on this film for solidification of the capacitor dielectric material.

Images