Capacitor component, use of capacitor component and method of manufacturing same

Abstract

An improved capacitor component is provided that includes a heat sink and a winding in direct thermal contact with the heat sink.

Description

[Technical field]

[0001] The present invention relates to a capacitor component, use cases for the capacitor component, and a corresponding method for manufacturing the capacitor component. [Background technology]

[0002] Capacitor components establish the physical embodiment of a capacitive element in an electrical circuit. Generally, capacitor components have good electrical and mechanical properties, such as high capacitance, small spatial dimensions, and mechanical robustness. It is also desirable for the capacitor components to withstand high current densities.

[0003] Capacitor components are used in DC link applications, for example on power supplies, as well as in hybrid or electric vehicles, for example, where electrical energy is stored in a battery and required by an electric motor. An inverter electrically converts the stored electrical DC energy, available from a battery or, for example, from a rectifier, into the corresponding voltage and current required by the electric motor. However, during operation of such an inverter, ripples or spikes may appear in the voltage and / or current. Corresponding capacitor components help to reduce the harmful effects of the spikes and ripples.

[0004] A capacitor system is known from WO2013 / 026645A2 or WO2018 / 122044A1. Summary of the Invention [Problem to be solved by the invention]

[0005] However, capacitor components with improved electrical and mechanical properties are desired. Specifically, capacitor components with improved thermal properties and improved electrical integration into the circuit environment are desired. Additionally, the capacitor components should have reduced system self-inductance and reduced spatial dimensions while maintaining a degree of mechanical stability. Additionally, what is needed are capacitor components with increased seismic resistance and capacitor components that can prevent overpressurization in the chamber by controlled gas diffusion.

[0006] Furthermore, such a capacitor component is adapted to meet typical voltage or current or current density requirements, e.g. in DC link systems of electric vehicles. To that end, a capacitor component is provided according to the independent claims. The dependent claims provide preferred embodiments. [Means for solving the problem]

[0007] The capacitor component includes a first winding element and a heat sink. The first winding element is in direct thermal contact with the heat sink.

[0008] Such a capacitor component offers improved thermal properties compared to conventional capacitor components in which the windings are housed in an additional can, e.g., an aluminum can, which establishes an additional heat-conducting resistance element when heat is to be dissipated from the winding elements of the capacitor component to the environment, such as an external heat sink.

[0009] Furthermore, the direct integration of the first winding element of the capacitor component with the heat sink and corresponding monolithic integration enhances mechanical stability and reduces spatial dimensions: the heat sink essentially serves as a housing for the first winding element of the capacitor component.

[0010] The capacitor component can include one or more additional winding elements disposed in direct thermal contact with the heat sink. Two or more winding elements of the capacitor component are electrically connected in parallel to provide increased capacitance and increased current density of the capacitor component.

[0011] Each of the winding elements may comprise a cathode foil, an anode foil and an electrical insulator between the two foils. Each of the two foils may be electrically connected to one of the two electrodes of the capacitor component. In particular, the two electrodes of the capacitor component may be galvanically insulated from each other.

[0012] The winding element or elements can be selected from cylindrical windings and flat winding elements. Cylindrical windings are obtained by stacking foils and insulation between the foils and rolling them into a cylindrical shape. Flat winding elements can be obtained, for example, from pressed round windings by rolling the corresponding foils and insulation around a flat object such as a rectangular sheet, or by stacking materials to obtain a winding element with substantially longer extensions in two orthogonal lateral directions perpendicular to the winding axis.

[0013] It is possible for the first winding element to have two electrodes, one of which can be in direct electrical contact with the heat sink.

[0014] Such a configuration allows for good thermal coupling between the winding elements and the heat sink, as well as small spatial dimensions. Furthermore, the direct contact also allows for high current densities in the capacitor components.

[0015] The heat sink may then function as one of the electrodes of the capacitor component, specifically, the heat sink may function as the cathode of the capacitor component.

[0016] The capacitor component may further comprise a sealing for isolating the wound element from the external environment.

[0017] The sealing may include a cover, which may be made of a material selected from metal, glass, hard paper, and a rubber layer.

[0018] The heat sink includes a cavity and an opening through which a winding element is inserted into the cavity during manufacture. After inserting the winding element into the cavity, each opening is sealed in a sealing process utilizing a cover.

[0019] The cover may be provided with a ring or insert made of rubber, which allows the cavity to be sealed in a simple manner with the winding element on the inside, essentially resulting in an airtight seal.

[0020] The capacitor component may further comprise a stabilizing element, which may be selected from a vibration damping element, a potting element, a mechanical latch, a rib, and a pin.

[0021] The stabilization element can be monolithically integrated in the material of the heat sink and can furthermore compress the winding element radially or axially.

[0022] In particular, the stabilizing element consists of a cover. For example, during the manufacture of the capacitor component, the capacitor component is sealed by forcing the cover through an opening into a cavity of a heat sink. In the cavity of the heat sink, a winding element is arranged. By forcing the cover into the cavity, for example, an axial force acts on the winding element which axially compresses the winding element. In particular, this axial compression mechanically stabilizes the winding element.

[0023] For example, the stabilization element comprises further elements, such as ribs arranged along the circumference of the cavity, which can radially compress the winding element. In particular, the further elements can radially compress the winding element, for example while the cover is being pressed into the cavity. Alternatively or additionally, the winding element can be slightly deformed by axial compression, for example a heat sink exerting an additional radial force on the winding element. Thus, the winding element can be axially compressed, or radially compressed, or axially and radially compressed by the stabilization element.

[0024] Furthermore, the potting element or potting material can mechanically stabilize the wound element. For example, a filling material such as epoxy or silicone can bond the wound element to a heat sink while curing inside the cavity. In particular, the cavity can be open or sealed with a cover, for example, while the filling material cures.

[0025] In such a configuration, the stabilization element protects the capacitor component and its components during phases of strong acceleration, such as mechanical resonance. Moreover, the stabilization element can be used to exert a predetermined force, essentially fixing the winding element in its steady-state position. And, by arranging the winding element so that it cannot change its position relative to the heat sink, mechanical stability is increased. Furthermore, a further improvement in the thermal coupling of the winding element to the heat sink is obtained, and the occurrence of unfilled spaces in the heat sink is prevented, which results in an increase in the packing density of the capacitor component, the capacitance per unit volume, and the current density per unit volume.

[0026] The capacitor component can have a corresponding open side and a bottom part. In the open side, an opening towards the cavity is arranged. The bottom part is arranged opposite the open side of the heat sink. A recess in the bottom part of the heat sink allows for the arrangement of a corresponding connection to one electrode of the two foils, for example access to the cathode. The provision of the recess simplifies the connection of the cathode while maintaining good stability and integration density.

[0027] The electrical coupling between the wound element and the heat sink can have an ohmic resistance between the wound element and the heat sink of 0.6 mΩ or less, as compared to a single wound element capacitor component welded to the negative bus bar, for example, via a soldered star element.

[0028] Additionally, the capacitor component may include a pressure relief element.

[0029] The pressure relief element may be embodied as a diffusion membrane that allows pressure relief from the interior of the heat sink to the external environment.

[0030] Such a pressure relief element can act as a protective element to prevent overpressure during operation of the capacitor component.

[0031] It is possible to weld the cathode foil directly to the heat sink, which therefore allows a good thermal and electrical coupling between the winding element and the heat sink, resulting in good thermal and electrical properties, especially high current densities.

[0032] The heat sink may be constructed from a material selected from aluminum and / or copper.

[0033] Furthermore, the first winding element may comprise an electrode made of a material selected from aluminum and / or titanium and / or carbon.

[0034] Furthermore, when the separator material comprises or consists of a material selected from paper or synthetic fiber tissue, or a combination of both, the first wound element comprises the separator material between the electrodes. The complete wound element may be impregnated with a liquid electrolyte, impregnated / coated with a polymer dispersion, or impregnated / coated with a combination of both.

[0035] Additionally, the heat sink may include connection terminals for mechanically attaching and electrically connecting the heat sink to an external circuit environment.

[0036] In particular, the connection terminals may be configured to be mechanically attached to and electrically connected to a busbar, for example a busbar of a DC link between an energy source, such as a battery, and an inverter.

[0037] The capacitor component may have a longitudinal extension L, a first lateral extension W, and a second lateral extension H. The longitudinal extension L is perpendicular to the longitudinal section. The first lateral extension W is perpendicular to the transverse section. The second lateral extension H is perpendicular to the front surface. The longitudinal extension L may be 10 mm to 400 mm. The first lateral extension W may be 10 mm to 150 mm. The third lateral extension H may be 10 mm to 150 mm.

[0038] In particular, the capacitor components can be configured to fit into a corresponding rectangular parallelepiped having the dimensions described above.

[0039] As mentioned above, the capacitor components may be used as DC link capacitors, for example in electric vehicles, hybrid vehicles or power supplies.

[0040] A method for manufacturing such a capacitor component may include the following steps.

[0041] Providing a heat sink and a first winding element; inserting the wound element into the heat sink such that the first wound element is in direct thermal contact with the heat sink; The first wound element is sealed within a heat sink.

[0042] Furthermore, direct thermal contact can be provided via a welding process in which the first winding element or the electrode foil of the first winding element is welded to the heat sink.

[0043] The capacitor components can be aluminum capacitors, polymer electrolytic capacitors, or hybrid polymer electrolytic capacitors.

[0044] The heat sink may specifically function as the cathode connection for the capacitor component.

[0045] The capacitor component can accommodate customer applications such as 48 volt inverters, on-board chargers, and power supplies. However, the device can also be used in higher voltage applications. The capacitance of the capacitor component can be between 100 and 20,000 μF, for example 3,000 μF. The heat sink can include an interface or cooling fins for electrically and thermally coupling the heat sink to a cooling circuit. Additionally, the heat sink is configured to be connected to a Peltier component and a fan configured to blow air on the heat sink.

[0046] Various options are possible for the manufacture of the capacitor components. In particular, a uniaxially wound element can be assembled with a cathode foil, an anode foil and a paper separator above and below the cathode foil to obtain a cylindrical shape of the wound element. A filling material can be used to mechanically fix the wound element in the heat sink.

[0047] A curl tool for encapsulating a capacitor component as described above has an active surface for pressing the cover into the cavity and simultaneously curling the heat sink edge towards the cover to seal the cavity.

[0048] Specifically, the active surface of the tool is provided with a portion of the active surface essentially parallel to the cover and another portion of the active surface at an angle to the heat sink edge or segment of the heat sink edge such that the heat sink edge or heat sink edge element initially directed at the tool is bent toward the cover to permanently seal the cavity. The bent edge or edge element then permanently presses the cover toward the cavity from outside the cavity. [Brief description of the drawings]

[0049] [Figure 1] For better illustration, a perspective view of the unfolded capacitor components and a possible curl tool is shown. [Diagram 2] For better illustration, a perspective view of the unfolded capacitor components and a possible curl tool is shown. [Diagram 3] Although multiple tabs per foil are possible, one possible arrangement of foils and corresponding connecting tabs is shown. [Figure 4] Although multiple tabs per foil are possible, one possible arrangement of foils and corresponding connecting tabs is shown. [Diagram 5] 1 shows the components of a capacitor assembly prior to sealing the cavity. [Figure 6] The corresponding sealed cavities are shown. [Figure 7] The corresponding sealed cavities are shown. [Figure 8] The corresponding sealed cavities are shown. [Figure 9] 1 shows the components of a capacitor part before encapsulation. [Figure 10] Shown are encapsulated components. [Figure 11] 1 shows the components of a capacitor part before encapsulation. [Figure 12] Shown are encapsulated components. [Figure 13] Shown are encapsulated components. [Figure 14]A capacitor component having four turn elements and a corresponding capacitor component having a flat single turn element are shown, respectively. [Figure 15] The possibility of connecting the capacitor components to the busbars is shown. [Figure 16] It presents further possibilities for mounting and electrically connecting the capacitor components to the external environment, for example to a busbar. [Figure 17] Further possibilities for mounting and electrically connecting the capacitor components to the external environment, such as to a busbar, are presented. [Figure 18] Further possibilities for mounting and electrically connecting the capacitor components to the external environment, such as to a busbar, are presented. [Figure 19] Further possibilities for mounting and electrically connecting the capacitor components to the external environment, such as to a busbar, are presented. [Figure 20] Further possibilities for mounting and electrically connecting the capacitor components to the external environment, such as to a busbar, are presented. [Figure 21] Further possibilities for mounting and electrically connecting the capacitor components to the external environment, such as to a busbar, are presented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] The main operating principle and details of the preferred embodiment are illustrated in the attached schematic drawing.

[0051] FIG. 1 shows a perspective view of four capacitive elements WI contained in a common cavity of a heat sink HS. The heat sink HS comprises mounting holes MH for mechanically and electrically connecting the heat sink HS to an external circuit environment. Furthermore, the heat sink HS comprises recesses RE on the bottom side. In particular, there is one recess RE for each winding element WI, which facilitates the routing of the cathode electrodes of the capacitor components CC to the heat sink HS. Furthermore, a sealing element SE is arranged at the opening of the cavity of the heat sink HS. There is a common sealing element SE for each of the four winding elements WI. The sealing element SE comprises four holes. The four holes allow the electrical contacts EC to be led to the outside of the capacitor components CC.

[0052] 1 further shows a possible tool for sealing the cavity of the capacitor component CC: the tool TO can be used to press the sealing SE into position above the winding element WI so that the sealing SE is laterally embedded by the neck NE of the heat sink HS.

[0053] Figure 2 shows a similar arrangement, but with differently shaped mounting holes MH, and furthermore shows a cross section through a possible sealing scenario SE, in which the through holes establishing the connection to the external contacts EC are visible.

[0054] Figures 3 and 4 show the internal structure of the corresponding winding element WI. The winding element comprises a cathode foil CF and an anode foil AF and a corresponding paper sheet PA arranged between the two foils CF, AF. Furthermore, an additional paper foil PA is arranged "behind" the cathode foil CF. Furthermore, the winding element comprises connection tabs CT (one or more per foil) for establishing contact to the external environment. In particular, the cathode foil CF can be electrically connected to the heat sink HS, while the anode foil AF can be electrically connected via a connection tab, which can be arranged through the sealing SE. Furthermore, the connection tabs CT and the corresponding foils CF, AF can be electrically and mechanically connected via welding spots WS. The welding can be performed by cold welding.

[0055] 4 shows a similar arrangement, however, with both connection tabs CT arranged towards the same side of the winding element.

[0056] Thus, Fig. 3 shows a uniaxially wound element and Fig. 4 shows a snap-in wound element assembled via corresponding foil windings. Within the capacitor component the winding elements can be mechanically fixed, for example using welding of a connection tab to a heat sink in the case of axially wound elements, or using a potting material for fixing.

[0057] Figures 5 and 6 show the possibility of sealing the cavity against the external environment of the capacitor component. Figure 5 shows a sealing SE, which comprises a glass, rubber or plastic insulator. The anode rivet is placed in the center of the sealing SE. Via the anode connection AC, the anode of the winding element can be accessed from the external circuit environment. In this case, the heat sink HS establishes the cathode connection.

[0058] Additionally, optionally, a diffusion membrane DM may be provided to relieve overpressure.

[0059] The weld points WP can be used to connect the connection tabs of the winding elements to the external anode connection AC.

[0060] Correspondingly, Figure 6 shows the previously described configuration in a sealed state, where the sealing is disposed essentially flush with the upper surface of the heat sink HS. Optionally, a filler material PO mechanically stabilizes the bottom of the wound element within the heat sink HS. A cover CO can be welded to the heat sink to establish an essentially hermetic seal.

[0061] Figures 5 and 6 essentially show a capacitor component with a single winding element, whereas Figures 7 and 8 show a capacitor component with multiple winding elements, for example four winding elements. In Figure 7 the capacitor component is provided with a flat common anode AN, whereas in the configuration according to Figure 8 each of the four winding elements has its own anode connection to the circuit environment.

[0062] The lower parts of Figures 7 and 8 show the possibility of providing individual separation between the wound elements in separate cavities in the heat sink.

[0063] 9 and 10 show open and closed versions of the single wound capacitor component, in the closed state the heat sink edge HSE is curled onto the top side of the cover to secure the seal.

[0064] Specifically, a curl tool TO as shown in Figures 1 and 2 can be used to seal the cavity. The tool TO has an active surface positioned toward the capacitor component. The tool TO can be used to press the cover into the top of the cavity and simultaneously curl the heat sink edge HSE toward the cover CO to seal the cavity CV. The active surface of the tool is configured such that one portion of the active surface is essentially parallel to the cover while another portion of the active surface is provided at an angle to the heat sink edge segment, so that the heat sink edge segment that initially points to the tool is bent toward the cover to permanently seal the cavity. The bent edge or edge element then permanently presses the cover toward the cavity from outside the cavity.

[0065] 11 and 12 show the possibility of providing a cover in the form of hard paper with a rubber layer and the option of providing an inner protective layer curled at the case wall.

[0066] FIG. 13 shows a corresponding encapsulation method utilizing hard paper in a version of the capacitor component having multiple four wound elements contained within a common cavity of a heat sink HS.

[0067] 14 shows the possibility of arranging several cylindrical winding elements, each with a connection tab CT, and also the possibility of arranging a single flat winding element in the cavity of the heat sink HS. In the case of arranging a single flat winding element in the cavity of the heat sink, the flat winding element may have several connection tabs arranged on the upper surface of the heat sink HS. Several flat winding elements are also possible in a similar configuration.

[0068] 15 shows the possibility of mounting the body of the capacitor component, essentially realized by a heat sink HS, to the external circuit environment, in particular to a busbar BB. The connection is established into the busbar BB via a connection insert CI, for example a copper insert, which is screwed into the heat sink, for example into the aluminum body of the heat sink.

[0069] In contrast, FIG. 16 shows the possibility of providing a contact plate CP on the busbar BB, such that a corresponding connection area of ​​the heat sink HS can be welded to the contact plate CP of the busbar BB.

[0070] 17 shows a further possibility for mounting the heat sink HS to the busbar BB. Each longitudinal side of the heat sink HS can be fixed to a corresponding mounting area, for example via two screws SC.

[0071] Figure 18 shows a further perspective view of the mounting method shown in Figure 17. In particular, Figure 18 shows the possibility of providing the collar COL against the upper surface at the sealing of the heat sink HS, so as to provide a connection area where the collar COL is connected to a busbar.

[0072] Fig. 19 shows a further possibility of attaching the heat sink HS to the busbar BB. The heat sink HS comprises an L-shaped connection area LSCA, such that the busbar BB is welded to the vertical part of the L-shaped connection area. The number of weld points can be 1, 2, 3, 4 and more. In particular, a plurality of 2 or more is preferred to stabilize the attachment area against torque forces.

[0073] 20 and 21 show further degrees of integrating the capacitor components into external systems such as system cooling circuits (eg, water-cooled, air-cooled) and semiconductors.

[0074] The capacitor component is not limited by the technical features described above or shown in the drawings. The capacitor component may comprise further mounting connections and electrical connections that further integrate and connect the capacitor component electrically and mechanically to the external environment.

[0075] This patent application claims priority from German patent application DE 102022111476.7, the disclosure of which is incorporated herein by reference. [Explanation of symbols]

[0076] AC Anode Connection ACT Anode Connection Tab AF Anode Foil BB Busbar CC Capacitor Parts CF cathode foil CI Connection Insert CO Cover COL Color CP Contact Plate CT Connection Tab cv cavity DM Diffusion Membrane EC external contact HS Heatsink HSE Heatsink Edge LSCA L-shaped connection area MH mounting hole NE Neck PA Paper PO filling RE recess SE sealing TC Thermal Connection TO Sealing Tool WI Wound element WS Welding Spot

Claims

1. a first winding element and a heat sink; The first winding element is in direct thermal contact with the heat sink.

2. The capacitor component of claim 1 comprising one or more additional winding elements in direct thermal contact with the heat sink.

3. The capacitor component of claim 1 or 2, wherein the one or more winding elements are selected from at least one of a cylindrical winding, a flat winding, and a stack.

4. 3. The capacitor component of claim 1, wherein the first winding element has two electrodes, one electrode being in direct electrical contact with the heat sink.

5. The capacitor component of claim 4 , wherein the heat sink provides an external contact for the capacitor component.

6. The capacitor component of claim 1 or 2, further comprising a sealing for isolating the wound element from the external environment.

7. The capacitor component of claim 6 , wherein the sealing comprises a cover constructed from a material selected from metal, glass, hard paper, a rubber layer, or combinations thereof.

8. The capacitor component of claim 7 , wherein the cover further comprises a ring or insert constructed of rubber, plastic, or glass.

9. 3. The capacitor component of claim 1 or 2, further comprising a stabilizing element selected from a vibration damping element, a filler element, a mechanical latch, a rib, and a pin.

10. 10. The capacitor component of claim 9, wherein the stabilization element is monolithically integrated in the material of the heat sink and / or radially or axially compresses the winding element.

11. The capacitor component of claim 10 comprising an open surface, a bottom surface, and a recess in the bottom surface.

12. The capacitor component according to claim 1 or 2, wherein the ohmic resistance between the wound element and the negative bus bar is 0.6 mΩ or less.

13. The capacitor component of claim 1 or 2, further comprising a pressure relief element.

14. The capacitor component of claim 13 , wherein the pressure relief element is a diffusion membrane that allows pressure relief from the interior of the heat sink to an external environment.

15. The capacitor component of claim 1 or 2, wherein the cathode foil is directly welded to the heat sink.

16. the heat sink is made of a material selected from one of Cu and Al; the first winding element comprises an electrode made of a material selected from Al, Ti, carbon and / or combinations thereof; 3. The capacitor component of claim 1 or 2, wherein the first wound element includes a separator material between the electrodes, the separator material being composed of a material selected from paper or synthetic fiber tissue or a combination of both, and the complete wound element may be impregnated with a liquid electrolyte or impregnated / coated with a polymer dispersion or a combination of both.

17. 3. The capacitor component according to claim 1, wherein the heat sink comprises connection terminals for mechanically attaching and electrically connecting the heat sink to an external circuit environment.

18. 20. The capacitor component of claim 17, wherein the connection terminal is configured to be mechanically attached and electrically connected to the bus bar.

19. A longitudinal extension L perpendicular to the longitudinal section; a first lateral extension W perpendicular to the transverse plane; a second lateral extension H perpendicular to the front surface; having 10 mm≦L≦450 mm, 10 mm ≦ W ≦ 100 mm, 3. The capacitor part according to claim 1, wherein 10 mm≦H≦100 mm.

20. using a sealing element (cover disk) including a rubber layer, said sealing element (cover disk) having a non-cylindrical shape, and an open end of the heat sink is conformally pressed into said rubber layer of said cover disk along the circumference of said non-cylindrical sealing element (cover disk); providing a seal for the winding element inside the heat sink and a mechanical fixation of the winding element by pressing the winding element against the bottom of the heat sink; 3. A capacitor component according to claim 1 or 2, wherein the pressing force for fixing the winding element is controlled by a predefined distance between the sealing element (cover disk) and the bottom of the heat sink (after closing or sealing of the capacitor component).

21. Using one of the following methods: a washer element made of copper-aluminium clad material, the copper part being in contact with the copper busbar and the aluminium part being in contact with the heat sink, by means of a screw connection with the washer element; - Direct welded contact of the copper busbar onto the heat sink by friction stir welding by the copper contact elements (strips / plates) which are welded to the heat sink and to which copper busbars are then connected, - copper busbars are connected onto copper contact elements (inserts) which fit gas-tightly into holes in the heat sink by means of turning and pressing, by a copper-clad contact element (dual material strip / plate / busbar) connected to the heat sink, the Al part being connected to the heat sink and the copper part being free to connect with a copper busbar, 3. The capacitor component of claim 1 or 2, further comprising a connection between an aluminum heat sink of the capacitor component and the copper bus bar.

22. 3. The capacitor component of claim 1, wherein the thermal contact between the capacitive element surface and the heat sink has a thermal contact resistance of less than 6 K / W.

23. 3. Use of a capacitor component according to claim 1 or 2 as a DC link capacitor.

24. A method for producing a capacitor component according to claim 1 or 2, comprising the steps of: Providing a heat sink and a first winding element; inserting the first winding element into the heat sink such that the first winding element is in direct thermal contact with the heat sink; The method of manufacturing further comprises sealing the first wound element within the heat sink.

25. 3. A curl tool for sealing a capacitor component as claimed in claim 1 or 2, comprising an active surface for pressing a cover into a cavity and simultaneously curling a heat sink edge towards the cover to seal the cavity.

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