Support element, capacitor component arrangement and method for manufacturing a capacitor component

Abstract

Support element (9), a film strand can be wound onto it to form a base body (2) for a capacitor component (1), and which can be separated from the base body (2), wherein the support element has a bottom surface (11) and a separating element (12) on the bottom surface (11), wherein the separating element (12) forms a radially inwardly projecting projection and has a recess (13), wherein the support element (9) is formed from a strip and is ring-shaped and has a slot with a control angle other than 0°.

Description

[0001] The invention relates to a support element, a capacitor component arrangement and a method for manufacturing a capacitor component.

[0002] A capacitor component could, for example, be a power capacitor suitable for use in a radially symmetrical installation space. In particular, the capacitor component can be used as a DC link capacitor in the DC link of an inverter.

[0003] Devices for winding capacitors are known from DE 18 95 216 U, wherein a winding core is spread open by receiving mandrels.

[0004] Devices for winding capacitors are known from JP 2004 - 095 610 A, wherein a band formed into a ring-shaped structure is used as the winding core.

[0005] Winding devices are known from US 2004 / 0 113 011 A1, wherein a winding core has various segments that can be rotated relative to each other.

[0006] Winding devices are known from CH 322 112 A, wherein a winding core can have slots guided through the core on different paths.

[0007] One object of the present invention is to provide an improved support element. Another object of the description is to provide a capacitor component with improved properties, for example, with an increased volume fill factor. A further object of the invention is to provide an improved method for manufacturing the capacitor component. The volume fill factor indicates the ratio of the geometric volume of a component or module to the volume actually used in a technical application.

[0008] These problems are solved according to the invention by a support element having the features of claim 1 and by a capacitor-component arrangement and a method, each according to one of the further independent claims. Advantageous embodiments of the invention are the subject of the further claims.

[0009] A capacitor component is specified which has a base body, wherein the base body is formed by winding a film strand onto a support element and subsequently separating the support element from the base body.

[0010] The base body preferably comprises a stack of films with several internal electrodes and dielectric films arranged between them. Preferably, the dielectric films are polymer films. The dielectric films can be metallized on at least one outer surface. In this case, the internal electrodes are formed by the metallization of the dielectric films. Preferably, the metallized polymer films are arranged one above the other such that dielectric layers and metallic layers alternate in the film stack along the surface normal of the films.

[0011] The base body can further comprise one or more separating films made of an insulating material. Preferably, the separating films divide the base body into several capacitors.

[0012] The metallized dielectric foils can be wound into a capacitor winding, for example, a ring-shaped capacitor winding. The end faces of this capacitor winding, which are parallel to the surface normal of the foils, can be at least partially coated with a metallization. This metallization is also called a Schoop layer.

[0013] The basic body of the capacitor is formed, for example, by the capacitor winding.

[0014] The capacitor component is designed such that it is free of the support element. Consequently, the capacitor component exhibits a high volume fill factor. The support element provides the necessary stability during manufacturing. In the finished component, the support element is not required.

[0015] Preferably, the base body is self-supporting without a support element. Accordingly, the wound film strand preferably provides sufficient stability so that the base body retains its shape even without a support element.

[0016] Preferably, the base body is ring-shaped. A ring-shaped base body is particularly suitable for installation in a radially symmetrical installation space. Preferably, other elements of the capacitor component are also ring-shaped. For example, ring-shaped elements for supplying voltage to the inner electrodes can be mounted on the base body.

[0017] Preferably, the ratio of the outer diameter to the inner diameter of the base body is less than or equal to 2.0. More preferably, the ratio is less than or equal to 1.5, and particularly preferably less than or equal to 1.25. With such a ratio of outer diameter to inner diameter, no excessive mechanical stresses act on the capacitor component even after the support element is separated.

[0018] According to the invention, a support element is provided onto which a film strand can be wound to form a base body for a capacitor component, and which is separable from the base body. The capacitor component can be designed as described above. Accordingly, the base body of the capacitor component described above can be formed by winding the film strand onto the support element and subsequently separating it from the support element.

[0019] Preferably, the support element is elastically deformable. For example, the support element can be made of an elastically deformable metal and / or have a shape that is elastically deformable. For example, the support element could have a small thickness.

[0020] An elastically deformable support element can absorb and compensate for forces generated during the winding and subsequent processing of the base body without being damaged. For example, the base body can be shrunk in a tempering process, generating radially inward forces that act on the support element. The elastic support element absorbs these forces and deforms accordingly. When these forces are no longer present at a later time, the support element returns to its original shape.

[0021] Preferably, the support element can be separated from the base body by elastic deformation. In the state connected to the base body, the support element can have a similar shape to the base body, for example, it can be ring-shaped. In particular, the base body can be in close contact with the support element.

[0022] Following the winding of the film strand, the deformation of the support element is initiated, for example by coupling the support element to a tool that exerts a corresponding force on the support element. The support element is thereby deformed in such a way that it is separated from the base body.

[0023] Preferably, the support element is designed such that it can be reused after separation from the base body. For this purpose, the support element is particularly elastically deformable, so that it is not damaged by deformation.

[0024] The support element is formed from a strip. The strip is shaped into a ring. The ring has a slit. Such a strip can easily be applied to a winding machine with a circular support.

[0025] Preferably, the support element comprises alloy spring steel. Preferably, the alloy spring steel has a small thickness so that the support element is elastically deformable.

[0026] The support element includes a separation element. The separation element may have a force application point for a tool to separate the support element from the base body. When the separation element acts on the force application point of the support element, the support element can preferably be elastically deformed. The separation element includes a recess. The recess may form a force application point for the separation tool.

[0027] In one embodiment, the support element for separating it from the base body has at least two separable components. These components could be made of dimensionally stable material. Dimensionally stable materials are less sensitive to environmental influences and can also withstand higher forces. In this case, the support element can be separated from the base body by separating the components of the support element from each other.

[0028] Another aspect concerns a capacitor-component arrangement comprising a capacitor component and a support element, wherein the support element is separable from the capacitor component. In particular, this can be the capacitor component and the support element described above.

[0029] Furthermore, a method for manufacturing a capacitor component is described, comprising the steps of: arranging a support element on a winding machine, winding a film strand onto the support element so that the film strand forms a base body of the capacitor component, separating the support element and the capacitor component from the winding machine, and separating the support element from the capacitor component. This method enables the manufacture of the capacitor component described above, using the support element described above.

[0030] Preferably, a spring element can be arranged on the winding machine. The spring element can facilitate the separation of the support element and the base body from the winding machine and can also absorb radial stresses that arise during the winding process.

[0031] Such a spring element is preferably manufactured from a plastic foam. Preferably, the individual pores of the foam form gas-tight, closed cells filled with a gas, for example, CO2. A spring element manufactured in this way has the advantage of being particularly resistant to material fatigue. The spring properties are not primarily caused by compression and decompression of a solid, but rather by the closed gas bubbles and thus by the compression and decompression of a gas volume.

[0032] The invention will now be explained in more detail with reference to exemplary embodiments and accompanying schematic figures.

[0033] They show: Fig. 1 a ring-shaped capacitor component, Fig. 2 a base body during the manufacturing process and a first embodiment for a support element, and Fig. 3 an alternative design of the support element.

[0034] Fig. Figure 1 shows a perspective view of a capacitor component 1 comprising a base body 2. The base body 2 is ring-shaped. The capacitor component 1 is a film capacitor, in which one-sided metallized dielectric films are wound one over the other within the base body 2. The base body 2 is radially symmetrical about an axis of symmetry 3. The base body 2 has a first end face 4 and a second end face 5 opposite it, the surface normals of the first end face 4 and the surface normals of the second end face 5 being parallel to the axis of symmetry 3. Each of the two end faces 4, 5 is at least partially covered with a metal layer, the so-called Schoop layer 6, 7. The first end face 4 has a first Schoop layer 6. The second end face 5 has a second Schoop layer 7.

[0035] Fig. Figure 1 shows the base body 2 of the capacitor component 1 after separation from a support element. The capacitor component 1 is thus free of a support element. During manufacturing, the base body 2 is wound onto the support element. Subsequently, the base body 2 is separated from the support element.

[0036] The base body 2 is self-supporting without the support element. Accordingly, the wound film provides sufficient stability so that the base body 2 retains its shape even without the support element.

[0037] The capacitor component 1 may further include elements for contacting the base body 2. For example, the capacitor component 1 may have busbars that contact the inner electrodes of the base body 2 with an external voltage source.

[0038] The base body 2 has a first and a second separating film 21, 22. The first and the second separating films 21, 22 can be made of a plastic, for example, polyimide. The first separating film 21 can be dimensioned such that it projects from the rest of the base body 2. In particular, the separating film 21 projects axially beyond the first Schoop layer 6. Accordingly, the first Schoop layer 6 is separated into two isolated areas. Furthermore, the second separating film 22 can be dimensioned such that it projects from the rest of the base body 2. In particular, the separating film 22 projects axially beyond the second Schoop layer 7. Accordingly, the second Schoop layer 7 is separated into two isolated areas.

[0039] Fig. Figure 2 shows the base body 2 of the capacitor component 1 during the manufacturing process. The base body 2 is wound on a winding machine. The winding machine has a round base body with a centering piece 8.

[0040] A support element 9, for example a circumferential core support, is arranged on the centering piece 8 of a winding machine. The support element 9 is a thin strip formed into a ring, with a first end 19 and a second end 20 of the strip not touching. Accordingly, the ends 19 and 20 of the strip form a slot 10 in the ring.

[0041] The support element 9 is elastically deformable. In particular, the strip comprises a metallic material that is elastically deformable. Preferably, the strip comprises alloyed spring steel.

[0042] The underside 11 of the support element 9 is mounted on the centering piece 8, with a separating element 12 arranged on the underside 11. The separating element 12 can be arranged at the first end 19 of the support element 9. The separating element 12 forms a radially inwardly projecting projection. The separating element 12 has a recess 13 which can serve as a point of force application for a separating tool 14.

[0043] In the embodiment shown here, the slot 10 formed by the two ends 19, 20 of the band has an opening angle of 0°. This opening angle is also referred to as the control angle. In another embodiment, the ends 19, 20 of the band can be chamfered, resulting in a control angle other than 0°. By appropriately selecting the control angle, the force required to separate the support element 9 from a base body 2 can be adjusted.

[0044] In a radial direction, a film strand is wound onto the support element 9 to form a base body 2 of the capacitor component 1. The film strand comprises two partially metallized films, for example, polymer films.

[0045] The basic body 2 can, for example, have an initial empty winding area in which the film strand is demetallized, a capacitor area in which the films of the film strand are metallized on one side and these metallizations form inner electrodes of the capacitor component, and an end empty winding area in which the film strand is demetallized.

[0046] More complex configurations of the basic body 2 are also possible. For example, the basic body 2 could have three isolated capacitors, with a second and a third capacitor connected to form a Y-capacitor. Accordingly, the second and third capacitors could be connected in series with each other and in parallel with a first capacitor.

[0047] The film strand is wound onto the support element 9 to form the base body 2 of the capacitor component 1. Mechanically resilient pads 15 are also arranged on the outside of the centering piece 8. The pads 15 are designed as so-called spring pads, for example, as strip-shaped spring pads. Such a spring pad 15 is preferably made of a plastic foam. Preferably, the individual pores of the foam form gas-tight, closed cells filled with a gas, for example, CO2. A spring pad 15 manufactured in this way has the advantage of being particularly resistant to material fatigue. The spring properties are not primarily caused by compression and decompression of a solid, but rather by the closed gas bubbles and thus by compression and decompression of a gas volume.

[0048] Each winding of the film strand exerts a radial force, the tape tension force, on the support element 9. These forces accumulate with each winding. Accordingly, an axial force and a radial force act on the fully wound base body 2 and on the support element 9, causing the support element 9 to contract elastically in both the radial and axial directions.

[0049] The slightly contracted support element 9 can be removed from the centering piece 8 of the winding machine together with the base body 2. A Schoop layer 6, 7 is then applied to the end faces 4, 5 of the base body 2. The Schoop layer 6, 7 is a metal layer applied to the end faces 4, 5 of the base body 2, which enables contact between the internal electrodes.

[0050] The base body 2 of the capacitor component 1 is then heated in a tempering process. Tempering causes the film strand to shrink, as polymers exhibit a shrinking effect when heated.

[0051] In the next step, a force is applied to the separation element 12 of the support element 9 by means of a separation tool 14, for example, an angled lever. This deforms the support element 9 and separates it from the base body 2. The separation element 12 is attached to the first end 19 of the support element 9. The first end 19 is pulled radially inwards, so that it detaches from the inside of the base body 2, to which it was previously positively engaged.

[0052] Furthermore, a force can be exerted on the separation element 12 in an axial direction via the separation tool 14. Accordingly, the separation element 12, and thus also the first end 19 of the support element 9 connected to it, moves axially out of the annular base body 2.

[0053] The support element 9 deforms elastically, the deformation of the support element 9 following the movement specified by the first end 19.

[0054] The support element 9 is only elastically deformed during the separation process. Therefore, the support element 9 can be reused to produce another base body 2. For this purpose, it can be reapplied to the centering piece 8 of the winding machine.

[0055] After the support element 9 is separated from the base body 2, the latter may relax slightly or deform slightly. The base body 2 is now self-supporting, meaning it no longer requires support elements 9. After the removal of the support element 9, a diameter reduction of approximately 1% of the base body 2 is to be expected.

[0056] Fig. Figure 3 shows an alternative, unclaimed embodiment of the support element 9 with a wound base body 2. The support element 9 has three components 16, 17, 18. Each of the three components 16, 17, 18 is ring-segment shaped. The three components 16, 17, 18 together form a ring. This ring is placed on a centering piece 8 of a winding machine, and the base body 2 is wound onto the ring.

[0057] The support element 9 and the base body 2 can then be separated together by the winding machine. Subsequently, the support element 9 can be disassembled into the three components 16, 17, 18 and thus separated from the capacitor component 1.

[0058] When using the two support elements 9 described here, a base body 2 is obtained that is free of the respective support element 9. Accordingly, the base body 2 or the capacitor component 1 has a very good volume filling factor. Reference symbol list 1 capacitor component 2 basic shapes 3. Axis of symmetry 4 first front 5 second front 6 first shift 7 second shift 8 Centering piece 9 Support element 10 slots 11 Underside of the support element 12 Separation element 13 Exclusion 14 Separation tools 15 mechanically spring-loaded pads 16 Component of the support element 17 Component of the support element 18 Component of the support element 19 first end of the support element 20 second end of the support element 21 first separating film 22 second separator film

Claims

[1] Support element (9), a film strand can be wound onto it to form a base body (2) for a capacitor component (1), and which can be separated from the base body (2), wherein the support element has a bottom surface (11) and a separating element (12) on the bottom surface (11), wherein the separating element (12) forms a radially inwardly projecting projection and has a recess (13), wherein the support element (9) is formed from a strip and is ring-shaped and has a slot with a control angle other than 0°. [2] Support element (9) according to claim 1, which is elastically deformable. [3] Support element (9) according to claim 2, which is separable from the base body (2) by elastic deformation. [4] Support element (9) according to one of claims 1 to 3, which is designed such that it is reusable after separation from the base body (2). [5] Support element (9) according to any one of claims 1 to 4, comprising alloyed spring steel. [6] Support element (9) according to any one of claims 1 to 5, wherein the separation element (12) is a force application point (13) for a tool (14) for separating the support element (9) from the base body (2). [7] Capacitor component arrangement comprising a capacitor component (1) and a support element (9) according to any one of claims 1 to 6, wherein the support element (9) is separable from the capacitor component (1). [8] Method for manufacturing a capacitor component (1) comprising the steps: A) Arranging a support element (9) according to one of claims 1 to 6 on a winding machine, B) Winding a strand of film onto the support element (9) so that the strand of film forms a base body (2) of the capacitor component (1), C) Separating the support element (9) and the capacitor component (1) from the winding machine, D) Separating the support element (9) from the capacitor component (1) using the separating element (12) and its projection. [9] Method according to claim 8, wherein a spring element (15) on the winding machine enables elastic deformation during winding.

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