Aluminum electrolytic capacitor adopting high-heat-capacity aluminum shell
By adopting a high-heat-capacity aluminum shell design in small aluminum electrolytic capacitors, the problem of unsatisfactory heat dissipation is solved, achieving efficient heat dissipation of the core and improved structural strength, thus extending the life and reliability of the capacitor.
Patent Information
- Application Number
- CN202511724510.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-03-20
AI Technical Summary
Because a pressure relief valve is installed at the bottom of the aluminum shell, small aluminum electrolytic capacitors cannot be structurally reinforced, resulting in poor heat dissipation and affecting capacitor performance and lifespan.
The design adopts a high heat capacity aluminum shell. By setting protruding ribs and reinforcing ribs at the bottom of the inner cavity of the aluminum shell, the heat capacity is increased. A fixing column and pressure relief valve mechanism are set inside the aluminum shell to achieve positioning, pushing, support and efficient heat dissipation of the core package.
This improves the heat dissipation efficiency of aluminum electrolytic capacitors, extends their lifespan and reliability, and enhances their structural strength.
Smart Images
Figure CN121709429A_ABST
Abstract
Description
Technical fields:
[0001] This invention relates to the internal structure design of small aluminum electrolytic capacitors. Specifically, the capacitor solves the problems of internal core fixing and support and efficient heat conduction by using a high heat capacity aluminum shell, thereby improving the capacitor's performance, lifespan and reliability. Background technology:
[0002] Aluminum electrolytic capacitors are important basic electronic components, widely used in many fields such as consumer electronics, industrial electrical, automotive, aerospace and military industries.
[0003] The lifespan and reliability of aluminum electrolytic capacitors are important factors affecting their performance, and temperature is the most direct factor determining lifespan and reliability. Generally, for every 10°C increase in ambient temperature or 5°C increase in the capacitor's hot spot temperature, the lifespan of aluminum electrolytic capacitors is reduced by half and the failure rate increases by 6-8 times. Therefore, reducing temperature is an effective way to improve the lifespan and reliability of capacitors.
[0004] Users often increase the air cooling rate to lower the ambient temperature, while capacitor manufacturers develop electrolytes and electrode foil materials with lower ESR values to reduce hot spot temperatures. Aluminum electrolytic capacitors consist of a core made of positive and negative electrode foils and electrolytic paper, which is then immersed in electrolyte and placed in a cylindrical aluminum shell, sealed with a rubber stopper or cover. Heat is mainly generated at the contact surface between the positive electrode foil and the electrolyte, concentrated primarily in the center of the core, near the hot spot. Due to the heat generated by the core under ripple current load, the capacitor temperature rises, causing the electrolyte in the core to dry out and leading to capacitor failure. Therefore, capacitors require internal heat dissipation structures to cool the internal components.
[0005] Large (SCREW Type) bolt-on aluminum electrolytic capacitors, because their pressure relief valve is located on the electrode lead terminal cover, can utilize a negative electrode extension structure for heat dissipation. This means that the negative electrode foil at the bottom of the core package, in contact with the aluminum shell, is widened and extends beyond the core package plane to ensure close contact with the bottom of the aluminum shell. Simultaneously, the bottom aluminum shell is reinforced with materials such as thickening, reinforcing ribs, and core package mounting posts. This allows heat from inside the core package to be conducted to the bottom of the aluminum shell via the negative electrode foil, and then radiated outwards from the aluminum shell. This negative electrode extension structure establishes an efficient heat conduction path from the core package hotspot to the aluminum shell, effectively improving the heat dissipation efficiency of the SCREW large aluminum electrolytic capacitor and significantly enhancing its performance and lifespan.
[0006] Small (Radial Type / Snap-In Type) leaded and horn-shaped aluminum electrolytic capacitors have a pressure relief valve at the bottom of the aluminum shell. To ensure its effective opening, the bottom aluminum shell cannot be too thick, nor can it have reinforcing ribs or mounting posts. This makes it impossible to strengthen the structural weight. Even if the core uses a negative electrode extension structure design, the thin and light aluminum shell does not have enough heat capacity to establish an efficient heat conduction path, so the heat dissipation effect is not ideal. Summary of the Invention:
[0007] This invention provides a high heat capacity aluminum shell design for small (radial type / snap-in type) leaded and horn-shaped aluminum electrolytic capacitors, which solves the problems of fixing, pushing and supporting the core package, while helping to efficiently conduct heat from the core package to the outside of the aluminum shell.
[0008] The technical solution adopted is as follows: a uniform thin-walled cylinder and the “X” and “Y” grooves engraved on its bottom are used as pressure relief valves. The aluminum shell, which is simply covered by the core package, is redesigned into a spatial three-dimensional frame structure aluminum shell that has the functions of positioning, pushing, supporting and conducting heat for the core package inside the cavity, and at the same time has a pressure relief valve mechanism. The heat capacity value of the aluminum shell structure has a great influence on the heat conduction efficiency. The aluminum shell can increase the heat capacity and improve the heat conduction efficiency of the core package to the outside.
[0009] Based on the actual situation, the bottom of the inner cavity of the high heat capacity aluminum shell is the "hub" for the heat transfer from the core package to the outside. Thickening it here to give it a larger structural mass is particularly important for the rapid heat transfer from the core package.
[0010] Specifically, a raised rib is provided at the bottom of the inner cavity of the aluminum shell to push and compact the negative electrode extension of the core package, thereby increasing the effective contact area and reducing the contact thermal resistance.
[0011] Furthermore, axially extended reinforcing ribs are added to the inner wall of the aluminum shell cavity to enhance the structural strength of the aluminum shell cavity and facilitate the axial conduction and heat dissipation of heat to the outer surface of the aluminum shell.
[0012] Specifically, the high heat capacity aluminum shell ensures stable positioning and assembly of the core package. A fixing post is set at the bottom of the cavity and inserted into the core roll hole in the center of the core package, which not only fixes the position of the core package but also helps to improve the heat conduction in the center of the core package.
[0013] Furthermore, the fixing post can be extended to a position flush with the capacitor sealing plug or cover plate, so that it acts as a support post, which helps to strengthen the overall axial structural strength of the capacitor and protect against compression damage to the core package.
[0014] Specifically, the aluminum casing can be in the traditional cylindrical shape, or it can be elliptical or square, etc.
[0015] Furthermore, the internal cavity of the aluminum shell can be a traditional cylindrical shape, or it can be an ellipse or a square shape, etc.
[0016] Furthermore, a single cavity within the aluminum casing can accommodate multiple core packages, which facilitates the miniaturization of capacitor products. Figure 9 );
[0017] The attached pressure relief valve mechanism consists of two parts: the valve body and the air passage.
[0018] Specifically, depending on whether the valve body and the aluminum housing exist independently, the valve body can be divided into integrated type and separate type;
[0019] Furthermore, referring to the manufacturing process of ordinary aluminum shells, the valve body is made by engraving "X" and "Y" grooves on the thin wall of the traditional aluminum shell. The one-piece valve body and air passage can be manufactured in one step at the same time as the aluminum shell, so as to improve efficiency and reduce costs.
[0020] Specifically, the air passage is the channel through which the gas inside the aluminum shell flows to the outside. It can be set at the bottom or side wall of the aluminum shell cavity. One or more air passages can be set, and the entrance and exit of the passage can be circular or square, etc.
[0021] Furthermore, air passages can be omitted in certain circumstances;
[0022] Specifically, the valve body is a component that allows pressurized gas inside the cavity to be released and passed through under limited air pressure conditions. The discrete valve body can be made of materials such as rubber, plastic, and metal.
[0023] Furthermore, the discrete valve body can be made of a single material or composed of multiple materials; it can be a single part or a combination of components.
[0024] Specifically, the valve body can be installed on the inlet side of the air passage or on the outlet side;
[0025] Furthermore, depending on the actual product requirements, the aluminum housing can be configured with one air passage to work with one valve body, or multiple air passages to work with one valve body.
[0026] Specifically, the discrete valve body can be assembled with the aluminum shell through bonding, welding, or sealing methods such as clamping and riveting;
[0027] This invention transforms the simple assembly of a lightweight, thin aluminum shell housing and covering the core package into a precision assembly where the aluminum shell positions, supports, pushes, conducts heat, and dissipates heat from the core package. The pressure relief valve mechanism has also been redesigned. The use of a high-heat-capacity aluminum shell significantly improves the rapid conduction and dissipation of heat from the core package, enhancing the performance, lifespan, and reliability of the aluminum electrolytic capacitor, while also increasing its structural strength. Attached image description:
[0028] Figure 1 This is an image of the external appearance of the upper cavity of a standard aluminum shell.
[0029] Figure 2 This is a view of the valve body from below, with a standard aluminum casing.
[0030] Figure 3 The top view of the internal cavity of the one-piece valve body aluminum shell.
[0031] Figure 4 This is a lower view of the aluminum housing of the integrated pressure relief valve mechanism.
[0032] Figure 5 This is a top view of the internal cavity of the aluminum housing of the discrete valve body.
[0033] Figure 6 This is a bottom view of the aluminum housing of a discrete pressure relief valve mechanism.
[0034] Figure 7 This is a schematic diagram of an aluminum electrolytic capacitor assembly using a discrete valve body and a high-heat-capacity aluminum shell.
[0035] Figure 8 This is a complete appearance diagram of an aluminum electrolytic capacitor assembly using a discrete valve body and high heat capacity aluminum shell.
[0036] Figure 9 This is a schematic diagram of a high-heat-capacity aluminum shell cavity multi-core package design.
[0037] The numbers in the diagram represent the following:
[0038] 1. Core Packaging
[0039] 11. Core-coated cathode foil extension section
[0040] 12. Core-packed electrode lead strip
[0041] 13. Core packaged and secured with adhesive tape
[0042] 2. Ordinary aluminum casing
[0043] 21. Aluminum shell cavity
[0044] 22. Pressure relief valve at the bottom of the aluminum housing
[0045] 3. High heat capacity aluminum shell
[0046] 31. Aluminum shell cavity
[0047] 32. Aluminum-cased pressure relief valve
[0048] 321. Aluminum-cased pressure relief valve - air passage
[0049] 322. Aluminum-cased pressure relief valve - valve body
[0050] 33. Aluminum shell central fixed support column
[0051] 34. Protruding ribs at the bottom of the inner cavity of the aluminum shell.
[0052] 35. Reinforcing ribs on the side walls of the aluminum shell cavity
[0053] 4. Sealing cover plate
[0054] 41. Electrode lead-out terminals
[0055] 42. Core package push-up boss
[0056] 5. Insulating tubing Detailed implementation method:
[0057] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Features in the embodiments can be combined with each other. In the following embodiments, those skilled in the art will readily recognize that some features can be replaced or omitted by other materials or methods in different situations. In some cases, related operations are not shown or described in the specification to avoid obscuring the core parts of the present invention with excessive description. Those skilled in the art can fully understand the related operations based on the description in the specification and general technical knowledge in the field.
[0058] The following are preferred embodiments:
[0059] like Figure 1 The image shows a typical uniform thin-walled aluminum shell, with an internal cylindrical cavity for accommodating the core package.
[0060] like Figure 2 The image shows a standard, uniform, thin-walled aluminum shell. An "X" groove is engraved on the thin wall at the bottom of the shell to serve as a pressure relief valve inside the cavity.
[0061] like Figure 3 The high heat capacity aluminum shell cavity is shown to have a fixed support column at the bottom center, raised ribs arranged at the bottom of the cavity and reinforcing ribs extending to the side wall of the cavity, and an air passage 321 for multiple pressure relief valve mechanisms distributed in a staggered manner with the raised ribs. The valve body, which is integrally formed with the aluminum shell, is the thin wall of the aluminum shell at the bottom of the air passage, which separates the inside of the cavity from the external passage of the aluminum shell.
[0062] like Figure 4 The image shows the bottom view of the high heat capacity aluminum shell of the one-piece valve body. On the outer side of the thin wall at the bottom of the air passage of the internal cavity of the aluminum shell, there are multiple engraved "Y" shaped grooves, which are used as valve body for the internal pressure relief mechanism of the cavity.
[0063] like Figure 5The image shows a high heat capacity aluminum shell. Inside the cavity, there are fixed support columns 33 at the bottom center, raised ribs 34 arranged at the bottom of the cavity, reinforcing ribs 35 extending to the side wall of the cavity, and air passages 321 for multiple pressure relief valve mechanisms staggered with the raised ribs. The air passages connect the inside of the cavity with the outside of the aluminum shell.
[0064] like Figure 6 The image shows the bottom view of the high heat capacity aluminum shell of the discrete valve body. Multiple air passages 321 are distributed at the bottom of the aluminum shell and communicate with the internal cavity of the aluminum shell. A discrete aluminum valve body 322 covers all the air passage outlets. The aluminum valve body 322 and the aluminum shell 3 are assembled by sealing methods such as welding and bonding.
[0065] like Figure 7 The diagram shows the assembly of a high heat capacity aluminum electrolytic capacitor with a discrete valve body and aluminum shell. The core 1 is placed inside the aluminum shell cavity, and the negative electrode extension 11 contacts and pushes against the protruding rib at the bottom of the aluminum shell. The electrode terminal 41 of the cover plate 4 inside the shell is fused or riveted to the electrode lead strip 12 of the core 1. The inner side of the cover plate 4 has a boss 42 that contacts and presses against the core 1 during assembly, so that the two ends of the core 1 are fixed and pushed against by the protruding rib 34 at the bottom of the aluminum shell cavity and the boss 42 of the cover plate, respectively.
[0066] like Figure 8 The image shown is an assembled appearance of a high heat capacity aluminum electrolytic capacitor with a discrete valve body. The bottom of the aluminum valve body 322 covers all air passages and is sealed with epoxy resin to the aluminum shell. The outside is covered with a heat-shrinkable insulating tubing shell 5 for insulation.
[0067] like Figure 9 The diagram shows a high heat capacity aluminum shell 3 with an elliptical appearance. The internal cavity is also elliptical, and two core packages 1 are placed side by side into the internal cavity 31 of the aluminum shell 3 for fixed assembly.
Claims
1. An aluminum electrolytic capacitor using a high heat capacity aluminum shell, comprising a core, a high heat capacity aluminum shell, and a sealing plug or cover plate; wherein the internal cavity of the high heat capacity aluminum shell is provided with an auxiliary structure for fixing, pushing, and supporting the core; and wherein the high heat capacity aluminum shell is provided with an internal pressure relief valve mechanism.
2. The high heat capacity aluminum shell as described in claim 1 is characterized by: thickening the bottom of the cavity with raised ridges to push and compact the extended part of the core package negative electrode, thereby reducing the contact thermal resistance.
3. The high heat capacity aluminum shell as described in claim 1 is characterized by: axially extending reinforcing ribs on the inner wall of the cavity, which enhance the structural strength of the aluminum shell and facilitate the axial conduction and heat dissipation of heat to the outer surface of the aluminum shell.
4. The high heat capacity aluminum shell as described in claim 1 is characterized in that: a fixing post is provided at the bottom of the cavity and inserted into the core winding hole in the center of the core package to fix the core package. The fixing post can extend to a position flush with the sealing plug or cover plate of the capacitor, thereby improving the heat conduction in the center of the core package and strengthening the axial structural strength of the capacitor.
5. The high heat capacity aluminum shell as described in claim 1 is characterized in that it can be a traditional cylindrical shape, or an ellipse or a square shape, etc., and the internal cavity can be a traditional cylindrical shape, or an ellipse or a square shape, etc.
6. The aluminum electrolytic capacitor with a high heat capacity aluminum shell as described in claim 1 is characterized in that: a single cavity inside the aluminum shell can accommodate multiple cores, which is beneficial for miniaturization of the capacitor.
7. The aluminum electrolytic capacitor with a high heat capacity aluminum shell as described in claim 1, wherein the aluminum shell pressure relief valve mechanism is characterized in that: the valve body can be integral or discrete, wherein the integral valve body adopts the traditional aluminum shell thin wall engraved with "X" "Y" and other grooves as the valve body, and the valve body and air passage are manufactured in one step simultaneously with the aluminum shell.
8. The aluminum electrolytic capacitor with a high heat capacity aluminum shell as described in claim 1, wherein the aluminum shell pressure relief valve mechanism is characterized in that: the air passage inlet can be set at the bottom or side wall of the cavity, one or more air passages can be set, the passage inlet and outlet can be round or square or irregular shape, the valve body can be set on the air passage inlet side or on the outlet side, one air passage can be set with one valve body, or multiple air passages can be set with one valve body.
9. The aluminum electrolytic capacitor with a high heat capacity aluminum shell as described in claim 1, wherein the aluminum shell pressure relief valve mechanism is characterized in that: the discrete valve body can be made of rubber, plastic or metal, and can be composed of a single material or multiple materials, and can be a single part or a combination of components.
10. The aluminum electrolytic capacitor with a high heat capacity aluminum shell as described in claim 1, wherein the discrete pressure relief valve mechanism is characterized in that the discrete valve body can be assembled with the aluminum shell by means of bonding, welding, or sealing methods such as clamping or riveting.