Capacitor component, use of capacitor

Abstract

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

Description

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

[0002] Capacitor components establish the physical implementation of capacitive components in electronic circuits. Generally speaking, capacitor components should have good electrical and mechanical properties, such as high capacitance, small spatial size and mechanical robustness. In addition, capacitor components are expected to withstand high current densities.

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

[0004] Capacitor systems are known from WO 2013 / 026645 A2 or from WO 2018 / 122044 A1.

[0005] However, it is desirable for capacitor components to have improved electrical and mechanical properties. Specifically, capacitor components with improved thermal performance and improved electrical integration into a circuit environment are desired. In addition, capacitor components should have reduced system self-inductance and reduced spatial dimensions while maintaining a certain degree of mechanical stability. Furthermore, capacitor components with increased vibration resistance and capacitor components that allow controlled gas diffusion to prevent overpressure within the chamber are desired.

[0006] Furthermore, such a capacitor component should be compatible with typical voltage or current or current density requirements in, for example, a DC link system of an electric vehicle. To this end, a capacitor component according to the independent claim is provided. The dependent claims provide preferred embodiments.

[0007] The capacitor component comprises 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 provides improved thermal performance compared to conventional capacitor components in which the windings are contained within an additional can, such as an aluminum can, which creates an additional thermally conductive resistance element when heat should be dissipated from the winding elements of the capacitor component to its environment (e.g., an external heat sink).

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

[0010] The capacitor component may include one or more additional winding elements also provided and adapted to be in direct thermal contact with the heat sink.Two or more winding elements of the capacitor component may be electrically connected in parallel to provide increased capacity and increased current density of the capacitor component.

[0011] Each of the winding elements may include a cathode foil and an anode foil and an electrical insulation between the two foils. Each of the two foils may be electrically connected to one of the two electrodes of the capacitor component. Specifically, the two electrodes of the capacitor component may be electrically isolated from each other.

[0012] One or more of the winding elements may be selected from cylindrical windings and flat winding elements. Cylindrical windings may be obtained by stacking foils and insulators between the foils and by winding them into a cylindrical shape. Flat winding elements may be obtained, for example, by winding corresponding foils and insulators around a flat object such as a rectangular sheet, from a flattened circular winding or by stacking materials to obtain a winding element that extends substantially longer in two orthogonal lateral directions perpendicular to the axis of the winding.

[0013] The first winding element can have two electrodes, while one electrode can be in direct electrical contact with the heat sink.

[0014] Such a configuration allows small space dimensions and good thermal coupling between the winding element and the heat sink. Furthermore, the direct contact also allows high current density of the capacitor components.

[0015] Then, the heat sink can act as one of the electrodes of the capacitor component. Specifically, the heat sink can act as the cathode of the capacitor component.

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

[0017] The sealing member may comprise a cover. The cover may comprise or consist of a material selected from metal, glass, cardboard, a rubber layer.

[0018] The heat sink may include a cavity and an opening, so that during manufacturing, the winding element is inserted into the cavity through the opening. After the winding element is inserted into the cavity, the corresponding opening is sealed with a cover in a sealing process.

[0019] The cover may also comprise an insert or a ring comprising or consisting of rubber. Such an insert or a ring allows the winding element to be sealed inside the cavity in a simple manner, thereby obtaining a substantially hermetic seal against the outside world.

[0020] The capacitor element may further comprise a stabilizing element. The stabilizing element may be selected from the group consisting of a damping element, a potting element, a mechanical latch, a rib and a pin.

[0021] The stabilizing element can be integrated monolithically in the material of the heat sink. Furthermore, the stabilizing element can compress the winding element radially or axially.

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

[0023] For example, the stabilizing element comprises further elements, such as ribs arranged along the periphery of the cavity, which can radially compress the winding element. Specifically, for example, the further elements can radially compress the winding element when the cover is pressed into the cavity. Alternatively or in addition, for example, the winding element can be slightly deformed due to the axial compression so that the heat sink applies additional radial forces to the winding element. Thus, the winding element can be compressed axially, radially, or axially and radially by the stabilizing element.

[0024] In addition, the potting element or potting material can mechanically stabilize the winding element. For example, a potting material such as epoxy or silicone can bond the winding element to the heat sink when it hardens or cures in the cavity. Specifically, for example, the cavity can be open or sealed with a cover when the potting material cures.

[0025] In such a configuration, the stabilizing element protects the capacitor component and its constituent elements during strong acceleration phases such as mechanical resonance. In addition, the stabilizing element can be used to apply a certain degree of force so that the winding element is essentially fixed to its steady-state position. The arrangement of the winding element is then such that the winding element cannot change its position relative to the heat sink, thereby increasing the mechanical stability. In addition, an additional improvement is obtained in the thermal coupling of the winding element to the heat sink, and the unfilled space in the heat sink is protected, thereby increasing the integration density of the capacitor component, the capacity per unit volume and the current density per unit volume.

[0026] The capacitor component may include a corresponding open side and a bottom side. An opening toward the cavity is arranged at the open side. The bottom side may be arranged opposite to the open side of the heat sink. The recess on the bottom side of the heat sink enables a corresponding connection to one electrode of the two foils, such as a channel to the cathode. The provision of the recess simplifies the connection to the cathode while maintaining good stability and integration density.

[0027] The electrical coupling between the winding element and the heat sink may result in an ohmic resistance between the winding element and the heat sink of 0.6 mΩ or less compared to a single winding element capacitor component welded to the negative busbar by, for example, welding a star element.

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

[0029] The pressure relief element may be realized as a diffusion membrane which enables pressure to be released from the interior of the heat sink to the external environment.

[0030] Such a pressure relief element may serve as a protective element against overpressure during operation of the capacitor assembly.

[0031] The cathode foil can be welded directly to the heat sink. Direct welding thus allows good thermal and electrical coupling between the winding element and the heat sink, thereby obtaining good thermal and electrical properties, in particular high current densities.

[0032] The heat sink may include or consist of a material selected from aluminum and / or copper.

[0033] Furthermore, the first winding element can comprise an electrode which comprises or consists of a material selected from the group consisting of 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 winding element may comprise the separator material between the electrodes and the complete winding element may be impregnated with a liquid electrolyte, or impregnated / coated with a polymer dispersion or a combination of both.

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

[0036] In particular, the connection terminal may be adapted and provided for mechanical mounting and electrical connection to a busbar, such as a busbar of a DC link between an inverter and a power source, such as a battery.

[0037] The capacitor component may have a longitudinal extension L, a first transverse extension W, and a second transverse extension H. The longitudinal extension L is perpendicular to the longitudinal plane. The first transverse extension W is perpendicular to the cross-sectional plane. The second transverse extension H is perpendicular to the frontal plane. The longitudinal extension L may be 10 mm or more and 400 mm or less. The first transverse extension W may be 10 mm or more and 150 mm or less. The second transverse extension H may be 10 mm or more and 150 mm or less.

[0038] In particular, the capacitor component may be adapted to fit into a corresponding cube having said dimensions.

[0039] As described above, the capacitor component may be used as a DC link capacitor in, for example, an electric vehicle, a hybrid vehicle, or a power supply.

[0040] The method of manufacturing a capacitor component as described above may include the following steps:

[0041] - providing a heat sink and a first winding element,

[0042] - inserting the winding elements into the heat sink such that the first winding element is in direct thermal contact with the heat sink,

[0043] - Sealing the first winding element in a heat sink.

[0044] Furthermore, direct thermal contact can be established via a welding process in which the first winding element or an electrode foil of the first winding element is welded to the heat sink.

[0045] The capacitor component may be an aluminum capacitor, a polymer electrolyte capacitor, or a hybrid polymer electrolyte capacitor.

[0046] The heat sink may in particular serve as a cathode connection for the capacitor component.

[0047] The capacitor component can be compatible with customer applications such as 48 volt inverters, on-board chargers, power supplies, etc. However, the component is also available for high voltage applications. The capacity of the capacitor component can be between 100 μF and 20,000 μF, for example 3,000 μF. The heat sink may include cooling fins or interfaces for electrically and thermally coupling the heat sink to a cooling circuit. In addition, the heat sink may be suitable for and provided for connection to a Peltier component or to a fan suitable for and configured to blow air to the heat sink.

[0048] There are different options for the production of the capacitor components. In particular, a single axial winding element can be assembled using cathode foil, anode foil and paper separators. A cylindrical shape of the winding element is obtained above and below the cathode foil. The winding element can be mechanically fixed in the heat sink using a potting material.

[0049] The crimping tool used to seal the above capacitor components has an active side that is used to press the cover into the cavity and simultaneously crimp the edge of the heat sink toward the cover to seal the cavity.

[0050] Specifically, the active side of the tool is configured so that a portion of the active side is substantially parallel to the cover, while another portion of the active side is disposed at an angle relative to the heat sink edge or a portion of the heat sink edge, so that the heat sink edge or heat sink edge element initially pointed toward the tool bends toward the cover to permanently seal the cavity. The bent edge or edge element then permanently pushes the cover from outside the cavity toward the cavity.

[0051] The central working principle and details of the preferred embodiment are shown in the schematic drawings. In the drawings:

[0052] For better explanation purpose, Figure 1 and Figure 2 A perspective view of a cut-away capacitor component and possible crimping tool is shown.

[0053] Figure 3 and Figure 4 A possible arrangement of foils and corresponding connecting pads is shown, while there may be multiple connecting pads per foil.

[0054] Figure 5 Elements of the capacitor assembly are shown before the cavity is sealed.

[0055] Figures 6 to 8 The corresponding sealed cavity is shown.

[0056] Similarly, Fig. 9 and Fig.11 shows the components of the capacitor assembly before sealing, and the corresponding Fig.10 and Fig.12 and Fig.13 The sealed components are shown.

[0057] Fig.14 A capacitor component with four individual winding elements and a corresponding flat single winding element are respectively shown.

[0058] Fig.15 A possible connection of capacitor components to a busbar is shown.

[0059] Figures 16 to 21 A further possibility is shown for mounting and electrically connecting the capacitor assembly to the external environment, such as a busbar.

[0060] Figure 1A perspective view of four capacitive elements WI contained in a common cavity of a heat sink HS is shown. The heat sink HS includes mounting holes MH to mechanically and electrically connect the heat sink HS to an external circuit environment. In addition, at the bottom side of the heat sink HS, the heat sink HS includes a recess RE. In particular, for each winding element WI, there is a recess RE, which simplifies the wiring of the cathode electrode to the heat sink HS of the capacitor component CC. In addition, 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 includes four holes, through which the electrical contact EC can be guided to the outside of the capacitor component CC.

[0061] Additionally, Figure 1 A possible tool for sealing the cavity of the capacitor component CC is shown. The tool TO may be used to press the seal SE into position over the winding element WI so that the seal SE is embedded in a lateral direction through the neck NE of the heat sink HS.

[0062] Figure 2 A similar configuration is shown in which the mounting hole MH is provided in a different shape. Figure 2 A section through a possible sealing element SE is shown, so that the through-holes establishing the connection to the external contacts EC are visible.

[0063] Figure 3 and Figure 4 The internal structure of the corresponding winding element WI is shown. 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. In addition, an additional paper foil PA is arranged "behind" the cathode foil CF. In addition, the winding element comprises a connecting piece CT (single or multiple connecting pieces per foil) for establishing contact with the external environment. Specifically, the cathode foil CF can be electrically connected to the heat sink HS, and the anode foil AF can be electrically connected via a connecting piece, which can be arranged to pass through the seal SE. In addition, the connecting piece CT and the corresponding foil CF, AF can be electrically and mechanically connected via a welding point WS. Welding can be performed via cold pressure welding.

[0064] Figure 4 A similar configuration is shown. However, both connection lugs CT are arranged towards the same side of the winding element.

[0065] therefore, Figure 3 shows a single axial winding element, and Figure 4A snap-in winding element assembled via winding of corresponding foils is shown.In the capacitor component, the winding element can be mechanically fixed, for example in the case of axial winding elements, by welding the connecting lugs to the heat sink or using a potting material for fixing.

[0066] Figure 5 and Figure 6 A possible scenario of sealing the cavity against the external environment of the capacitor components is shown. Figure 5 A seal SE is shown which comprises a glass, rubber or plastic insulation. An anode rivet is arranged in the center of the seal SE. Via the anode connection AC, access to the anode of the winding element is possible from the external circuit environment. In this case, the heat sink HS establishes the cathode connection.

[0067] Furthermore, a diffusion membrane DM is optionally provided in order to allow excess pressure to be released.

[0068] The welding point WP can be used to connect the connection piece of the winding element to the external anode connection AC.

[0069] Correspondingly, Figure 6 The previously described arrangement is shown in a sealed state, wherein the seal is arranged substantially flush with the top side of the heat sink HS. Optionally, the potting material PO mechanically stabilizes the bottom of the winding element within the heat sink HS. The cover CO can be welded to the heat sink to establish a substantially hermetic seal.

[0070] Figure 5 and Figure 6 Basically a capacitor component with a single winding element is shown, whereas Figure 7 and Figure 8 A capacitor component having a plurality of winding elements, for example four winding elements, is shown. Figure 7 In the embodiment, the capacitor part comprises a flat common anode AN, and in the embodiment according to Figure 8 In a configuration of , each of the four winding elements has its own anode connection to the circuit environment.

[0071] Figure 7 and Figure 8 The bottom part of FIG. 4 shows the possibility of providing separate partitions between winding elements in separate cavities in the heat sink.

[0072] Fig. 9 and Fig.10 The open and closed versions of a single winding capacitor component are shown, where in the closed state the heat sink edge HSE is crimped to the top side of the cover to ensure sealing.

[0073] Specifically, if Figure 1 and Figure 2The crimping tool TO shown can be used to seal the cavity. The tool TO has an active side arranged toward the capacitor component. The tool TO can be used to press the cover into the top of the cavity and simultaneously crimp the heat sink edge HSE toward the cover CO to seal the cavity CV. The active side of the tool is configured so that a portion of the active side is substantially parallel to the cover, while another portion of the active side is arranged at an angle relative to the heat sink edge portion so that the heat sink edge portion initially pointing toward the tool is bent toward the cover to permanently seal the cavity. The bent edge or edge element then permanently pushes the cover from the outside of the cavity toward the cavity.

[0074] Fig.11 and Fig.12 The possibility of providing a cover in the form of a cardboard with a rubber layer is shown, as well as the option of providing an inner protective layer that curls with the shell wall.

[0075] Fig.13 A corresponding sealing method using cardboard is shown in one version of a capacitor component having a plurality of four winding elements contained in a common cavity of a heat sink HS.

[0076] Fig.14 The possibility of arranging a plurality of cylindrical winding elements each having a connection tab CT is shown, as well as 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 heat sink cavity, the flat winding element may have a plurality of connection tabs arranged at the top side of the heat sink HS. In a similar configuration, a plurality of flat winding elements is also possible.

[0077] Fig.15 The possibility of mounting the body of the capacitor assembly to an external circuit environment, in particular a busbar BB, is shown, essentially achieved via a heat sink HS. The connection to the busbar BB is established via a connecting insert CI, for example a copper insert, which is screwed into the heat sink, for example into its aluminum body.

[0078] In contrast, Fig.16 It is shown the possibility of providing a contact plate CP at the busbar BB so that the corresponding connection area of ​​the heat sink HS can be welded to the connection plate CP of the busbar BB.

[0079] Fig.17 A further possibility of mounting the heat sink HS to the busbar BB is shown: Each longitudinal side of the heat sink HS can be fixed to a corresponding mounting area via, for example, two screws SC.

[0080] Fig.18 Shows Fig.17 . Specifically, Fig.18A possible situation is shown in which a collar COL is provided to the top side at the seal of the heat sink HS so that the collar COL provides a connection area to be connected to a busbar.

[0081] Fig.19 Another possible case of mounting the heat sink HS to the busbar BB is shown: the heat sink HS comprises an L-shaped connection area LSCA, so that the busbar BB is welded to the vertical part of the L-shaped connection area. The number of welding points can be one, two, three, four or more. In particular, a plurality of two or more is preferred to stabilize the mounting area against torque forces.

[0082] Fig. 20 and Fig.21 Additional levels of integration of capacitor components into external systems such as system cooling circuits (eg, water cooling, air cooling) and semiconductors are shown.

[0083] The capacitor component is not limited by the technical features described above or shown in the figures. The capacitor component may include additional mounting connectors and electrical connectors to further integrate the capacitor component and electrically and mechanically connect the capacitor component to the external environment.

[0084] This patent application claims the priority of German patent application DE 102022111476.7, the disclosure content of which is incorporated herein by reference.

[0085] Reference numerals list

[0086] AC: Anode connector

[0087] ACT: Anode connection plate

[0088] AF: Anode Foil

[0089] BB: Busbar

[0090] CC: Capacitor component

[0091] CF: Cathode Foil

[0092] CI: Connection Insert

[0093] CO: Cover

[0094] COL: Collar

[0095] CP: Connection plate

[0096] CT: Connector

[0097] CV: Cavity

[0098] DM: Diffuser membrane

[0099] EC: External Contact

[0100] HS: Radiator

[0101] HSE: Radiator Edge

[0102] LSCA: L-Shaped Connection Area

[0103] MH: Mounting holes

[0104] NE: Neck

[0105] PA: Paper

[0106] PO: Potting

[0107] RE: recess

[0108] SE: Seals

[0109] TC: Thermal Connection

[0110] TO: Sealing tool

[0111] WI: Winding Components

[0112] WS: welding point

Claims

1. A capacitor component, comprising: - a first winding element and a heat sink, in, - The first winding element is in direct thermal contact with the heat sink.

2. Capacitor component according to the preceding claim, comprising one or more additional winding elements in direct thermal contact with the heat sink.

3. The capacitor component according to claim 1, wherein: One or more winding elements are selected from cylindrical windings and / or flat windings and / or stacks.

4. The capacitor component according to claim 1, wherein: The first winding element has two electrodes, and one electrode is in direct electrical contact with the heat sink.

5. Capacitor component according to the preceding claim, wherein The heat sink establishes external contacts for the capacitor component.

6. The capacitor component according to any of the preceding claims, further comprising a seal for isolating the winding element from the external environment.

7. Capacitor component according to the preceding claim, wherein The seal comprises a cover comprising or consisting of a material selected from the group consisting of metal, glass, cardboard, a rubber layer or a combination of these.

8. Capacitor component according to the preceding claim, wherein The cover also includes an insert or ring comprising or consisting of rubber, plastic or glass.

9. The capacitor component according to one of the preceding claims, further comprising a stabilizing element selected from the group consisting of a damping element, a potting element, a mechanical latch, a rib, a pin.

10. Capacitor component according to the preceding claim, wherein The stabilizing element is monolithically integrated into the material of the heat sink and / or compresses the winding element radially or axially.

11. Capacitor component according to the preceding claim, comprising an open side and a bottom side and a recess in the bottom side.

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

13. The capacitor component according to any of the preceding claims, further comprising a pressure relief element.

14. Capacitor component according to the preceding claim, wherein The pressure relief element is a diffusion membrane that enables pressure to be released from the interior of the heat sink to the external environment.

15. The capacitor component according to claim 1, wherein: The cathode foil is welded directly to the heat sink.

16. Capacitor component according to one of the preceding claims, in, - the heat sink comprises or consists of a material selected from copper and / or aluminum, - the first winding element comprises an electrode comprising or consisting of a material selected from the group consisting of aluminum, titanium, carbon and / or a combination of these, - The first winding element comprises a separator material between the electrodes, wherein the separator material comprises or consists of a material selected from paper or synthetic fiber tissue or a combination of both, and the complete winding element is capable of being impregnated with a liquid electrolyte, or impregnated / coated with a polymer dispersion or a combination of both.

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

18. Capacitor component according to the preceding claim, wherein The connection terminal is adapted and provided for being mechanically mounted and electrically connected to the busbar.

19. The capacitor component according to claim 1, comprising: - a longitudinal extension L perpendicular to the longitudinal plane, - a first lateral extension W perpendicular to the lateral plane, and - a second lateral extension H perpendicular to the frontal plane, wherein 10mm≤L≤450mm, 10mm≤W≤100mm, 10mm≤H≤100mm.

20. The capacitor component according to claim 1, - Use of a sealing element (cover disc) comprising a rubber layer, wherein: The sealing element (cover plate) has a non-cylindrical shape, and the open end of the heat sink is conformally pressed into the rubber layer of the cover plate along the periphery of the non-cylindrical sealing element (cover plate), - providing a tight seal of the winding element inside the heat sink and a mechanical fixation of the winding element by pressing the winding element onto the bottom of the heat sink, - The pressing force for fixing the winding element is controlled by a fixed distance between the sealing element (cover disc) and the bottom of the heat sink (after closing / sealing the capacitor element).

21. The capacitor component according to any of the preceding claims, further comprising a connection between the capacitor aluminum heat sink and the copper busbar using one of the following methods: - via a threaded connection with a washer element, which can be made of a copper-aluminum clad material and which is placed so that the copper part is in contact with the copper busbar and the aluminum part is in contact with the heat sink, - Directly weld the copper busbar to the heat sink by friction stir welding, - via a copper contact element (strip / plate) soldered to the heat sink; a copper busbar is then connected to the copper contact element, - via a copper contact element (insert) which fits tightly into a hole in the heat sink by rotating and pressing; connecting the copper busbar to the copper contact element (insert); - Via a copper clad contact element (bi-material strip / plate / busbar) connected to the heat sink, such that its aluminium part is connected to the heat sink and its copper part is free to connect it with the copper busbar.

22. The capacitor component according to claim 1, wherein: The thermal contact between the capacitive element surface and the heat sink has a thermal contact resistance below 6K / W.

23. Use of a capacitor component according to one of the preceding claims as a DC link capacitor.

24. A method of manufacturing a capacitor component according to any one of claims 1 to 19, comprising the following steps: - providing a heat sink and a first winding element, - inserting the winding element into the heat sink so that the first winding element is in direct thermal contact with the heat sink, - Sealing the first winding element in the heat sink.

25. A crimping tool for sealing a capacitor component according to any one of claims 1 to 19 and 22, the crimping tool comprising: - an active side for pressing the cover into the cavity, and - Simultaneously crimping the edge of the heat sink towards the cover to seal the cavity.

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