A package structure of a capacitor

Abstract

The application provides a capacitor packaging structure, which comprises a heat-conducting shell with a placing cavity formed inside, a sealing cover, a capacitor core subassembly and a lead assembly. The sealing cover is arranged on the heat-conducting shell and is welded with the heat-conducting shell to form a sealed placing cavity. The capacitor core subassembly is arranged in the placing cavity and is in interference fit with the heat-conducting shell. The capacitor core subassembly comprises a cathode foil, an anode foil and electrolytic paper arranged between the cathode foil and the anode foil. The cathode foil comprises an extension part which extends to the electrolytic paper of the anode foil and is connected with the heat-conducting shell. The lead assembly is connected with the capacitor core subassembly and extends out of the placing cavity. The above structure improves the heat dissipation.

Description

Technical Field

[0001] This application relates to the field of capacitors, and more particularly to a capacitor packaging structure. Background Technology

[0002] As electronic devices evolve towards miniaturization, higher frequency, and higher power, the performance requirements for their core components—capacitors, especially aluminum electrolytic capacitors—are becoming increasingly stringent. During operation, particularly in high ripple current or high-temperature environments, the capacitor core, typically composed of anode foil, cathode foil, electrolytic paper, and electrolyte, generates Joule heat. If this heat cannot be effectively dissipated in time, the internal temperature of the capacitor will continue to rise, accelerating electrolyte evaporation and drying, leading to capacitance decay, increased ESR, severely shortened capacitor lifespan, and even thermal runaway failure.

[0003] In existing technologies, the heat generated by the capacitor core is mainly conducted through thermal interface materials such as thermally conductive adhesives and potting resins filling the gaps between the core and the outer casing. However, these materials themselves have a certain thermal resistance, and the filling process is difficult to guarantee completely uniform and tight contact, forming a significant heat transfer bottleneck and limiting further improvements in heat dissipation efficiency.

[0004] Therefore, a packaging structure that improves heat dissipation is needed. Utility Model Content

[0005] In view of this, it is necessary to provide a capacitor packaging structure that improves heat dissipation in order to solve the above problems.

[0006] Embodiments of this application provide a capacitor packaging structure, including:

[0007] The heat-conducting shell has an internal placement cavity;

[0008] A sealing cap is placed over the heat-conducting shell and welded to the heat-conducting shell to form a sealed placement cavity;

[0009] A capacitor core assembly is placed in the placement cavity and is interference-fitted with the heat-conducting shell. The capacitor core assembly includes a cathode foil, an anode foil, and electrolytic paper disposed between the cathode foil and the anode foil. The cathode foil includes an extension that extends to the anode foil and the electrolytic paper. The extension is in close contact with the heat-conducting shell.

[0010] The lead wire assembly is attached to the capacitor core assembly and extends out of the placement cavity.

[0011] In at least one embodiment of this application, the capacitor core assembly includes at least one circulation unit, and a plurality of the circulation units are fixedly connected to form the capacitor core assembly.

[0012] In at least one embodiment of this application, the loop units are arranged in a stacked manner as follows:

[0013] cathode foil;

[0014] A first electrolytic paper covers the first surface of the cathode foil;

[0015] The anode foil covers the surface of the first electrolytic paper that is away from the cathode foil;

[0016] The second electrolytic paper covers the surface of the anode foil that is away from the first electrolytic paper;

[0017] In this system, adjacent circulation units are connected by stacking the second electrolytic paper of the previous unit with the cathode foil of the next unit.

[0018] In at least one embodiment of this application, the cathode foil further includes an overlapping portion, the electrolytic paper is completely attached to one side of the overlapping portion, and the anode foil is completely attached to the other side of the overlapping portion;

[0019] The extension portion is circumferentially connected to the overlapping portion and integrally formed. The extension portion does not overlap with the anode foil and the electrolytic paper, and the end of the extension portion away from the overlapping portion is attached to the heat-conducting shell.

[0020] In at least one embodiment of this application, the plurality of said circulating units are fixed by wrapping with insulating tape;

[0021] The insulating tape covers the interface between adjacent circulation units.

[0022] In at least one embodiment of this application, the lead assembly includes:

[0023] Anode leads are attached and connected to the anode foil;

[0024] The cathode lead is attached to the cathode foil and extends into the placement cavity in the same direction as the anode lead.

[0025] In at least one embodiment of this application, the heat-conducting shell has an open end, and the connection between the sealing cover and the heat-conducting shell has a circumferential weld seam, thereby fixing the heat-conducting shell and the sealing shell together by welding.

[0026] In at least one embodiment of this application, the welding method is laser welding.

[0027] In at least one embodiment of this application, the capacitor's encapsulation structure further includes an explosion-proof valve, which is opened onto the outer surface of the aluminum shell.

[0028] In at least one embodiment of this application, the heat-conducting shell is an aluminum shell.

[0029] The capacitor encapsulation structure described above eliminates the thermal gaps of traditional filling materials by interfering with the capacitor core assembly and the heat-conducting shell; at the same time, the extension of the cathode foil directly and extensively adheres to the heat-conducting shell, efficiently dissipating the heat inside the core to the metal shell through a low thermal resistance path; combined with the rigid encapsulation of the welded seal, it ensures a long-term stable heat dissipation channel. Attached Figure Description

[0030] Figure 1 This is a perspective view of the capacitor packaging structure described in this application;

[0031] Figure 2 This is a front view of the capacitor packaging structure described in this application;

[0032] Figure 3 This is an assembly diagram of the capacitor packaging structure described in this application;

[0033] Figure 4 This is a schematic diagram of the internal structure of the capacitor's encapsulation structure described in this application;

[0034] Figure 5 This is a three-dimensional schematic diagram of the cathode foil described in this application;

[0035] Explanation of main component symbols

[0036] 100. Capacitor encapsulation structure; 10. Thermally conductive shell; 11. Placement cavity; 20. Sealing cap; 30. Capacitor core assembly; 31. Cathode foil; 311. Extension; 312. Overlapping portion; 32. Anode foil; 33. Electrolytic paper; 40. Lead assembly; 41. Anode lead; 42. Cathode lead; 12. Open end; 50. Explosion-proof valve. Detailed Implementation

[0037] The embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0038] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "back," and similar expressions used in this article are for illustrative purposes only.

[0039] This application provides a capacitor packaging structure, including: a heat-conducting shell, a sealing cap, a capacitor core assembly, and a lead assembly. A placement cavity is formed inside the heat-conducting shell. The sealing cap is disposed on the heat-conducting shell and welded to the heat-conducting shell to form a sealed placement cavity. The capacitor core assembly is placed within the placement cavity and is interference-fitted with the heat-conducting shell. The capacitor core assembly includes a cathode foil, an anode foil, and electrolytic paper disposed between the cathode foil and the anode foil. The cathode foil includes an extension that extends to the anode foil and the electrolytic paper, and the extension is bonded to the heat-conducting shell. The lead assembly is bonded to the capacitor core assembly and extends out of the placement cavity.

[0040] The capacitor encapsulation structure described above eliminates the thermal gaps of traditional filling materials by interfering with the capacitor core assembly and the heat-conducting shell; at the same time, the extension of the cathode foil directly and extensively adheres to the heat-conducting shell, efficiently dissipating the heat inside the core to the metal shell through a low thermal resistance path; combined with the rigid encapsulation of the welded seal, it ensures a long-term stable heat dissipation channel.

[0041] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] Please see Figures 1-5 This application provides a capacitor encapsulation structure 100, including: a thermally conductive shell 10, a sealing cap 20, a capacitor core assembly 30, and a lead assembly 40. The thermally conductive shell 10 has a placement cavity 11 inside. The sealing cap 20 covers the thermally conductive shell 10 and is welded to the thermally conductive shell 10 to form a sealed placement cavity 11. The capacitor core assembly 30 is placed inside the placement cavity 11 and is interference-fitted with the thermally conductive shell 10. The capacitor core assembly 30 includes a cathode foil 31, an anode foil 32, and electrolytic paper 33 disposed between the cathode foil 31 and the anode foil 32. The cathode foil 31 includes an extension 311 that extends to the anode foil 32 and the electrolytic paper 33, and the extension 311 is attached to the thermally conductive shell 10. The lead assembly 40 is attached to the capacitor core assembly 30 and extends out of the placement cavity 11.

[0043] Specifically, the heat-conducting shell 10 is made entirely of aluminum, which has excellent thermal conductivity. Alternatively, the heat-conducting shell 10 can be made of copper or aluminum alloy to improve thermal conductivity. The heat-conducting shell 10 has an internal cavity 11 for accommodating the capacitor core assembly 30. The heat-conducting shell 10 has an opening at one end for sealing after the core is assembled.

[0044] The sealing cap 20 covers the opening end 12 of the heat-conducting shell 10 and is fixed to the heat-conducting shell 10 by laser welding, forming a sealed placement cavity 11. Welding eliminates the circumferential weld seam between the sealing cap 20 and the heat-conducting shell 10, ensuring airtightness and pressure resistance. The welding and fixing of the sealing cap 20 ensures the cavity's airtightness and prevents electrolyte evaporation.

[0045] In addition to laser welding, resistance welding and friction welding can also be used, depending on cost and precision requirements.

[0046] The capacitor core assembly 30 is tightly embedded in the placement cavity 11 of the heat-conducting shell 10. The capacitor core assembly 30 and the heat-conducting shell 10 are connected by an interference fit, specifically, the extension 311 of the cathode foil 31 is attached to the heat-conducting shell 10. The structure of the capacitor core assembly 30 is composed of multiple circulating units stacked together. Each circulating unit includes a cathode foil 31, a first electrolytic paper 33, an anode foil 32, and a second electrolytic paper 33.

[0047] The lead assembly 40 includes an anode lead 41 and a cathode lead 42. The anode lead 41 and the cathode lead 42 are electrically connected to the anode foil 32 and the cathode foil 31, respectively, and are led out to the outside of the placement cavity 11 for connection with external circuits.

[0048] The explosion-proof valve 50 is located outside the heat-conducting shell 10. The explosion-proof valve 50 provides a safe release path to prevent explosion in case of abnormal temperature rise or internal gas accumulation.

[0049] The outer diameter of the capacitor core assembly 30 is slightly larger than the inner diameter of the heat-conducting shell 10 placement cavity 11, achieving an interference fit. This interference fit completely eliminates the thermal resistance introduced by traditional thermal interface materials such as thermally conductive adhesives and potting compounds. It ensures direct contact between the shell and the cathode foil 31 of the capacitor core assembly 30, improving thermal conductivity.

[0050] The cathode foil 31 is provided with an extension 311 that extends beyond the stacked area of ​​the anode foil 32 and the electrolytic paper 33, and directly adheres to a large area of ​​the inner wall of the heat-conducting shell 10. The extension 311 is connected to the overlapping portion 312 of the cathode foil 31 and integrally formed, which can be completed by calendering or punching.

[0051] The cathode foil 31 is also provided with an overlapping portion 312, which is the overlapping portion of the cathode foil 31 layer, the anode foil 32, and the electrolytic paper 33.

[0052] The extension 311 does not overlap with the anode foil 32 or the electrolytic paper 33, ensuring that the bonding area is only in metal contact and there is no insulating medium to block the heat path.

[0053] Furthermore, the contact area with the heat-conducting shell 10 is determined by setting the shape of the cathode extension 311. Preferably, the extension 311 and the overlapping portion 312 of the cathode are circumferentially connected and integrally formed.

[0054] The extension 311 can also be replaced by multiple evenly distributed lug-shaped extensions 311 instead of the annular structure.

[0055] The extension section 311 establishes the shortest heat conduction path from the cathode to the metal casing. This improves heat dissipation efficiency, reduces thermal resistance, and ensures long-term stable operation of the capacitor under high loads.

[0056] Each cycle unit consists of a cathode foil 31, a first electrolytic paper 33, an anode foil 32, and a second electrolytic paper 33, in sequence. Between adjacent cycle units, the cathode foil 31 of the later unit is in direct contact with the second electrolytic paper 33 of the previous unit, and they are stacked together.

[0057] The entire core assembly is spirally wound with insulating tape, such as polyimide tape, to cover the joint interfaces of each unit, thereby providing structural fixation and insulation protection.

[0058] Each layer of electrolytic paper 33 must completely cover the underlying metal foil to prevent short circuits. The tape wrapping interval should not exceed 5mm to ensure complete coverage of the seams. The number of circulation units is determined based on the required capacitance, typically 10-50 layers.

[0059] The anode lead 41 is welded or riveted to the end of the anode foil 32 away from the core, and the cathode lead 42 is similarly connected to the other end of the cathode foil 31. Both leads are led out along the opening direction of the heat-conducting shell 10.

[0060] Alternatively, the leads can be secured to the housing outlets via glass encapsulation, ceramic sleeves, or insulating adhesive to enhance electrical insulation and mechanical fixation.

[0061] The anode lead 41 and the cathode lead 42 can be led out in the same direction, in opposite directions, or bent to adapt to different installation requirements.

[0062] When a capacitor is in operation, heat will inevitably be generated inside the core due to the AC ripple current and the internal ESR. Because the capacitor core and the aluminum shell are tightly interference-fitted, and the cathode foil 31 is in close contact with the shell over a large area through the extension 311, a rapid heat dissipation channel is formed, and the heat is quickly conducted from the core and dissipated into the environment through the aluminum shell.

[0063] Therefore, the capacitor encapsulation structure 100 provided above eliminates the thermal gap of traditional filling materials by interfering with the capacitor core assembly 30 and the heat-conducting shell 10; at the same time, the extension 311 of the cathode foil 31 directly and extensively adheres to the heat-conducting shell 10, efficiently dissipating the heat inside the core to the metal shell through a low thermal resistance path; combined with the rigid encapsulation of the welded seal, a long-term stable heat dissipation channel is ensured.

[0064] The above description is merely an embodiment of this application. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this application, but these improvements all fall within the protection scope of this application.

Claims

1. A capacitor packaging structure, characterized in that, include: The heat-conducting shell has an internal placement cavity; A sealing cap is placed over the heat-conducting shell and welded to the heat-conducting shell to form a sealed placement cavity; A capacitor core assembly is placed in the placement cavity and is interference-fitted with the heat-conducting shell. The capacitor core assembly includes a cathode foil, an anode foil, and electrolytic paper disposed between the cathode foil and the anode foil. The cathode foil includes an extension that extends to the anode foil and the electrolytic paper. The extension is in close contact with the heat-conducting shell. The lead wire assembly is attached to the capacitor core assembly and extends out of the placement cavity.

2. The capacitor packaging structure according to claim 1, characterized in that, The capacitor core assembly includes at least one circulation unit, and multiple circulation units are fixedly connected to form the capacitor core assembly.

3. The capacitor packaging structure according to claim 2, characterized in that, The loop units are arranged in a stacked manner as follows: cathode foil; A first electrolytic paper covers the first surface of the cathode foil; The anode foil covers the surface of the first electrolytic paper that is away from the cathode foil; The second electrolytic paper covers the surface of the anode foil that is away from the first electrolytic paper; In this system, adjacent circulation units are connected by stacking the second electrolytic paper of the previous unit with the cathode foil of the next unit.

4. The capacitor packaging structure according to claim 1, characterized in that, The cathode foil also includes an overlapping portion, the electrolytic paper is completely attached to one side of the overlapping portion, and the anode foil is completely attached to the other side of the overlapping portion; The extension portion is circumferentially connected to the overlapping portion and integrally formed. The extension portion does not overlap with the anode foil and the electrolytic paper, and the end of the extension portion away from the overlapping portion is attached to the heat-conducting shell.

5. The capacitor packaging structure according to claim 2, characterized in that, Multiple of the aforementioned circulation units are secured by wrapping them with insulating tape; The insulating tape covers the interface between adjacent circulation units.

6. The capacitor packaging structure according to claim 1, characterized in that, The lead assembly includes: Anode leads are attached and connected to the anode foil; The cathode lead is attached to the cathode foil and extends into the placement cavity in the same direction as the anode lead.

7. The capacitor packaging structure according to claim 1, characterized in that, The heat-conducting shell has an open end, and the connection between the sealing cover and the heat-conducting shell has a circumferential weld seam, which fixes the heat-conducting shell and the sealing shell together by welding.

8. The capacitor packaging structure according to claim 1, characterized in that, The welding method is laser welding.

9. The capacitor packaging structure according to claim 1, characterized in that, The capacitor's encapsulation structure also includes an explosion-proof valve, which is located on the outer surface of the heat-conducting shell.

10. The capacitor packaging structure according to claim 1, characterized in that... The heat-conducting shell is made of aluminum.

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