An enhanced heat dissipation type box capacitor and a manufacturing method thereof

Abstract

This invention discloses an enhanced heat dissipation type box capacitor and its manufacturing method, relating to the field of capacitor technology. It includes: a hollow metal tube with multiple heat dissipation ribs arranged circumferentially on its outer wall; the lower ends of the heat dissipation ribs penetrate into the hollow metal tube and are provided with limiting plates; a connecting rod is provided inside the hollow metal tube, and the connecting rod abuts against each limiting plate to support the heat dissipation ribs; a core package, formed by overlapping and winding aluminum foil and polypropylene film around the heat dissipation ribs; both ends of the core package are coated with gold powder and welded with leads; the inner surface, outer surface, and both gold-plated ends of the core package are coated with an insulating ceramic layer; a box body with a cover; the core package is installed inside the box body; both ends of the hollow metal tube penetrate to the outside of the box body and the cover, respectively; both ends of the heat dissipation ribs abut against the box body and the cover, respectively; and the leads penetrate to the outside of the cover. This invention improves heat dissipation efficiency and avoids the problems of performance degradation and shortened service life.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and more specifically, to an enhanced heat dissipation type box capacitor and its manufacturing method. Background Technology

[0002] Capacitors are indispensable electronic components in electronic devices. Their core function is to store charge. They can play key roles in circuits such as DC blocking and AC passing, coupling, bypassing, filtering, tuning circuits, energy conversion and control. They are widely used in power electronics, industrial control, new energy, communications and other fields. Their working stability and service life directly determine the operational reliability of the whole equipment.

[0003] Currently, the mainstream manufacturing process for box-type capacitors involves placing a core package (or capacitor core) formed by winding a metallized thin film inside a metal casing, and then encapsulating and curing it with epoxy resin or other thermosetting plastics. This process has advantages such as mature technology and low manufacturing cost, and is widely used in the industry. However, with the continuous increase in the power density of electronic devices, especially under high current and high power operating conditions, the limitations of existing processes in terms of heat dissipation and maintenance are becoming increasingly apparent, specifically manifested in the following ways: On the one hand, during capacitor operation, the core generates Joule heat due to the current flowing through it, and this heat generation is even more intense under high current and high power conditions. Meanwhile, encapsulation materials such as epoxy resin generally have low thermal conductivity, forming a thermal resistance layer between the core and the metal casing. This prevents the heat generated by the core from being quickly conducted to the metal casing and dissipated to the outside. Simultaneously, heat inside the core is even more difficult to dissipate effectively, easily leading to localized high temperatures, accelerating the aging of the dielectric material, and consequently causing capacitor performance degradation and a shortened lifespan.

[0004] On the other hand, the epoxy resin injection forms an integrated structure, which provides good protection, but also makes the product difficult to disassemble and repair after failure. Usually, the whole product can only be replaced, which increases maintenance costs and wastes resources.

[0005] Therefore, we propose an enhanced heat dissipation type box capacitor and its manufacturing method to solve the above-mentioned technical problems. Summary of the Invention

[0006] In order to solve the technical problems existing in the prior art, the present invention proposes an enhanced heat dissipation type box capacitor and its manufacturing method.

[0007] This invention is achieved through the following technical solution: An enhanced heat dissipation type box capacitor includes: A hollow metal tube has multiple heat dissipation ribs arranged in a ring around its outer side wall. The lower ends of the heat dissipation ribs penetrate into the hollow metal tube and are provided with limiting plates. A connecting rod is provided inside the hollow metal tube, and the connecting rod abuts against each limiting plate to support the heat dissipation ribs. The core package is formed by overlapping and winding aluminum foil and polypropylene film onto the heat dissipation ribs. Both ends of the core package are coated with gold powder and soldered with leads. The inner surface, outer surface and the gold powder surfaces at both ends of the core package are coated with an insulating ceramic layer. The box body has a cover on its top, the core package is installed inside the box body, the two ends of the hollow metal tube pass through to the outside of the box body and the cover respectively, the two ends of the heat dissipation ribs are respectively pressed against the box body and the cover, and the lead wire passes through to the outside of the cover.

[0008] In a further technical solution, the cross-sectional dimensions at both ends of the connecting rod are smaller than the cross-sectional dimensions at the middle, forming a tapered guide section.

[0009] In a further technical solution, the cover is provided with a through hole that matches the lead wire, the cover is provided with a first mounting hole, the box body is provided with a second mounting hole on the side away from the cover, and the two ends of the hollow metal tube are respectively adapted to the first mounting hole and the second mounting hole for installation.

[0010] In a further technical solution, rubber sleeves are provided on the inner sides of the through hole, the first mounting hole, and the second mounting hole.

[0011] In a further technical solution, a support plate is provided at the upper end of the heat dissipation rib, and the top surface of the support plate is provided with anti-slip texture.

[0012] In a further technical solution, both ends of the connecting rod can be detachably connected to several heat sinks.

[0013] In a further technical solution, the contact surface between the core package and the support plate is coated with a thermally conductive silicone grease layer.

[0014] In a further technical solution, the insulating ceramic layer is alumina ceramic, aluminum nitride ceramic, or beryllium oxide ceramic.

[0015] In a further technical solution, an insulating sleeve is provided on the outer side of the lead wire.

[0016] A method for manufacturing an enhanced heat dissipation type box capacitor, comprising the following steps: S1. Insert the connecting rod into the hollow metal tube, so that the outer wall of the connecting rod presses against each limiting plate and pushes up the heat dissipation ribs. S2. Overlap aluminum foil and polypropylene raw film and wind them onto the raised heat dissipation fins to form a core package; S3. Pull the connecting rod out of the hollow metal tube to loosen the heat dissipation fins, and then remove the hollow metal tube from the core package. S4. Spray gold coating on both ends of the core package and solder the leads; S5. Spray an insulating ceramic layer onto the inner surface, outer surface, and gold-plated surfaces at both ends of the core package after step S4. S6. After applying a thermally conductive silicone grease layer to the surface of the support plate, reinsert the hollow metal tube into the core package, and then reinsert the connecting rod into the hollow metal tube so that the heat dissipation ribs are supported and pressed against the inner wall of the core package. S7. Install the core package into the box, and seal the box with the cover to complete the assembly of the enhanced heat dissipation box capacitor.

[0017] The technical solution of the present invention has at least the following beneficial effects: 1. The heat dissipation ribs of this invention have both structural support and heat conduction functions. By directly contacting the inner surface of the core package for heat transfer and constructing heat dissipation channels on the inner surface of the core package, the heat dissipated from the inner surface of the core package is continuously carried away by air circulation, realizing a dual heat dissipation mechanism, improving heat dissipation efficiency, effectively avoiding the accumulation of heat inside the core package and the formation of local high temperatures, ensuring long-term stable operation under high current and high power conditions, effectively delaying the aging of dielectric materials, and avoiding problems such as capacitor performance degradation and shortened service life.

[0018] 2. This invention replaces the traditional epoxy resin potting process with an insulating ceramic layer, which not only isolates the core package from the external components and ensures operational safety, but also, because the thermal conductivity of ceramic material is higher than that of epoxy resin, can quickly dissipate the heat generated by the core package, further improving heat dissipation efficiency.

[0019] 3. This invention uses the method of pressing the ends of the heat dissipation ribs against the box and the cover to fix the position of the hollow metal tube, thereby fixing the position of the core package. Since no epoxy resin injection process is used, the box and the cover can be disassembled. In case of failure, there is no need to replace the whole thing. Only the core package needs to be removed for inspection or replacement, which reduces maintenance costs, reduces resource waste, and saves the time of epoxy resin preparation, which can effectively improve production efficiency. Attached Figure Description

[0020] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure from another direction of the present invention; Figure 3 This is a schematic diagram of the internal structure of the present invention; Figure 4 This is a schematic diagram of the structure of the core package of the present invention wound on a hollow metal tube; Figure 5 This is an axial side view of the hollow metal tube of the present invention; Figure 6 This is a front view of the hollow metal tube of the present invention; Figure 7 This is a front view of the seal of the present invention; Figure 8 This is an axial view of the connecting rod with heat sink provided in this invention; Figure 9 This is a cross-sectional schematic diagram of the core package of the present invention.

[0021] Reference numerals in the attached drawings: 1-Hollow metal tube, 2-Heat dissipation ribs, 3-Limiting plate, 4-Connecting rod, 5-Core package, 6-Lead wire, 7-Box body, 8-Cap, 9-Conical guide, 10-Through hole, 11-First mounting hole, 12-Second mounting hole, 13-Support plate, 14-Heat dissipation fin, 15-Gold plating material, 16-Insulating ceramic layer. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example: See Figures 1-9 The present invention provides an enhanced heat dissipation type box capacitor, comprising: A hollow metal tube 1 has multiple heat dissipation ribs 2 arranged in a ring around its outer side wall. The lower end of the heat dissipation ribs 2 penetrates into the hollow metal tube 1 and is provided with a limiting plate 3. A connecting rod 4 is provided inside the hollow metal tube 1. The connecting rod 4 abuts against each limiting plate 3 to support the heat dissipation ribs 2. The core package 5 is made of aluminum foil and polypropylene film overlapped and wound on the heat dissipation ribs 2. Both ends of the core package 5 are coated with gold powder 15 and welded with lead wires 6. The inner surface, outer surface and the gold powder surfaces at both ends of the core package 5 are coated with insulating ceramic layer 16. The box body 7 has a cover 8 on its top. The core package 5 is installed inside the box body 7. The two ends of the hollow metal tube 1 pass through to the outside of the box body 7 and the cover 8, respectively. The two ends of the heat dissipation ribs 2 are pressed against the box body 7 and the cover 8, respectively. The lead wire 6 passes through to the outside of the cover 8.

[0024] The working principle of the box capacitor of the present invention is as follows: When the connecting rod 4 is inserted into the hollow metal tube 1, it pushes up the heat dissipation ribs 2 arranged in a ring around the hollow metal tube 1 by squeezing the limiting plates 3 outward, so that the upper end of the heat dissipation ribs 2 fits tightly against the inner surface of the core package 5. The heat dissipation ribs 2 have the dual functions of structural support and heat conduction. While ensuring the structural stability of the core package 5, they also act as a heat conduction bridge, quickly dissipating the heat on the inner surface of the core package 5 to the external environment through direct contact with the inner surface of the core package 5. At the same time, after the heat dissipation ribs 2 are lifted, the inner surface of the core package 5 is exposed. The strip-shaped gap formed between the inner surface of the core package 5, the heat dissipation ribs 2, and the hollow metal tube 1 can serve as a heat dissipation channel for the inner surface of the core package 5. With the air circulation inside the box 7, these channels continuously carry away the heat dissipated from the inner surface of the core package 5. This, together with the heat conduction of the heat dissipation ribs 2, achieves a dual heat dissipation mechanism, improves heat dissipation efficiency, and effectively avoids the accumulation of heat inside the core package 5 and the formation of local high temperatures. Furthermore, the inner surface, outer surface, and gold-plated ends of the core package 5 are all coated with an insulating ceramic layer 16, replacing the traditional epoxy resin potting process. This not only isolates the core package 5 from external components, ensuring operational safety, but also, due to the higher thermal conductivity of ceramic material compared to epoxy resin, allows for rapid heat dissipation from the core package 5, further improving heat dissipation efficiency. More importantly, the box capacitor of this invention uses the method of the heat dissipation ribs 2 pressing against the box body 7 and the cover 8, which fixes the position of the hollow metal tube 1, thereby fixing the position of the core package 5. Since no epoxy resin potting process is used, the box body 7 and the cover 8 can be disassembled. In case of failure, there is no need to replace the whole unit; only the core package 5 needs to be removed for inspection or replacement, reducing maintenance costs, minimizing resource waste, and saving the time of epoxy resin preparation, thus effectively improving production efficiency. Compared to box capacitors made by traditional processes, the box capacitor made by this invention, through the above design, can operate stably for a long time under high current and high power conditions, effectively delaying the aging of the dielectric material and avoiding problems such as capacitor performance degradation and shortened service life. It is worth mentioning that the size of the connecting rod 4 can be replaced, thereby adjusting the ejection distance of the heat dissipation rib 2, which allows for the fabrication of core packages 5 with different internal apertures. Simultaneously, to reduce the probability of jamming during the ejection process of the heat dissipation rib 2, its length can be shortened, and the heat dissipation rib 2 can be configured as a continuous multi-segment structure, thus improving operational convenience.

[0025] In one specific implementation, see Figure 3 , Figure 4 and Figure 5 The cross-sectional dimensions at both ends of the connecting rod 4 are smaller than those at the middle, forming a tapered guide section 9.

[0026] By designing tapered guides 9 at both ends of the connecting rod 4, the connecting rod 4 can be guided to quickly and accurately insert into the hollow metal tube 1, improving assembly convenience and efficiency.

[0027] In one specific implementation, see Figure 1 , Figure 2 and Figure 7 The cover 8 has a through hole 10 that matches the lead wire 6. The cover 8 has a first mounting hole 11. The box body 7 has a second mounting hole 12 on the side away from the cover 8. The two ends of the hollow metal tube 1 are respectively fitted and installed with the first mounting hole 11 and the second mounting hole 12.

[0028] The through hole 10, the first mounting hole 11, and the second mounting hole 12 provide precise positioning for the installation of the lead wire 6 and the hollow metal tube 1, simplifying the assembly process and ensuring product consistency during mass production, thereby improving the yield rate.

[0029] In one specific embodiment, rubber sleeves are provided on the inner sides of the through hole 10, the first mounting hole 11, and the second mounting hole 12.

[0030] By providing rubber sleeves inside the through hole 10, the first mounting hole 11, and the second mounting hole 12, their elastic buffering characteristics can effectively absorb the vibration and shock during the operation of the box capacitor, effectively avoid the wear and loosening of the lead wire 6 and the hollow metal tube 1, thereby ensuring the long-term stable operation of the box capacitor and extending its service life.

[0031] In one specific implementation, see Figure 5 and Figure 6 The upper end of the heat dissipation rib 2 is provided with a support plate 13, and the top surface of the support plate 13 is provided with anti-slip texture.

[0032] By setting a support plate 13 at the upper end of the heat dissipation rib 2, not only is a more stable support foundation provided for the core package 5, ensuring the stability of the core package 5 structure, but the contact area between the heat dissipation rib 2 and the inner surface of the core package 5 is also increased, further improving the heat conduction efficiency. Furthermore, by setting anti-slip textures on the top surface of the support plate 13, the frictional resistance with the inner surface of the core package 5 is increased, reducing the probability of the core package 5 sliding and ensuring the long-term stable operation of the box capacitor.

[0033] In one specific implementation, see Figure 8 Both ends of the connecting rod 4 are detachably connected to several heat sinks 14.

[0034] After the cap 8 is placed on the box body 7 and the box capacitor is assembled, heat sinks 14 can be added to both ends of the connecting rod 4. The size of the heat sink 14 can be set according to the heat dissipation requirements and space conditions. It can be installed by means of movable sleeve or threaded connection. By increasing the heat conduction area through the heat sink 14, heat can be quickly dissipated to the external environment, further accelerating the heat conduction speed and improving the heat dissipation efficiency.

[0035] In one specific embodiment, the contact surface between the core package 5 and the support plate 13 is coated with a thermally conductive silicone grease layer.

[0036] Thermal grease not only has a good thermal conductivity, accelerating heat transfer, but it can also fill uneven gaps that may exist on the surface of the support plate 13 during processing. Therefore, applying a thermal grease layer to the contact surface between the core package 5 and the support plate 13 can effectively improve thermal conductivity.

[0037] In one specific embodiment, the insulating ceramic layer 16 is an alumina ceramic, an aluminum nitride ceramic, or a beryllium oxide ceramic.

[0038] Alumina ceramics offer both good thermal conductivity and affordability; aluminum nitride ceramics provide near-metallic thermal conductivity, meeting the needs of high-performance applications; and beryllium oxide ceramics are suitable for specialized fields requiring extreme heat dissipation. Flexible selection based on product performance requirements and cost budgets achieves the optimal balance between heat dissipation performance and cost control.

[0039] In one specific embodiment, an insulating sleeve is provided on the outer side of the lead wire 6.

[0040] The insulating sleeve can isolate the lead 6 from external electrical contact, eliminate the risk of short circuit, ensure electrical safety, and at the same time prevent wear and extend the service life of the lead 6.

[0041] The present invention also provides a method for manufacturing an enhanced heat dissipation type box capacitor, wherein manufacturing an enhanced heat dissipation type box capacitor as described above includes the following steps: S1. Insert the connecting rod 4 into the hollow metal tube 1, so that the outer wall of the connecting rod 4 presses against each limiting plate 3, and pushes up the heat dissipation rib 2. S2. Overlap aluminum foil and polypropylene raw film and wind them onto the raised heat dissipation ribs 2 to form a core package 5. S3. Pull the connecting rod 4 out of the hollow metal tube 1, so that the heat dissipation rib 2 can be loosened, and then the hollow metal tube 1 is taken out of the core package 5. S4. Spray gold coating 15 onto both ends of the core package 5 and solder the lead wire 6. S5. Spray an insulating ceramic layer 16 onto the inner surface, outer surface and gold-plated surfaces at both ends of the core package 5 after the treatment in step S4. S6. After applying a thermally conductive silicone grease layer to the surface of the support plate 13, reinsert the hollow metal tube 1 into the core package 5, and then reinsert the connecting rod 4 into the hollow metal tube 1 so that the heat dissipation ribs 2 are supported and pressed against the inner wall of the core package 5. S7. Install the core package 5 inside the housing 7, and seal the housing 7 with the cover 8 to complete the assembly of the enhanced heat dissipation type box capacitor.

[0042] This method employs a step-by-step operation logic of "assembly-disassembly-reassembly" through the aforementioned steps: First, the core package 5 support frame, consisting of hollow metal tube 1, heat dissipation ribs 2, and connecting rods 4, is assembled; after the core package 5 is rolled, the support frame is disassembled, and the hollow metal tube 1 is removed to facilitate electrode preparation and spraying of the insulating ceramic layer 16; then, the support frame is reassembled, allowing the heat dissipation ribs 2 to support and abut against the inner surface of the core package 5; finally, the core package 5 is placed into the box 7 for sealing. This step-by-step operation ensures the molding accuracy and insulation integrity of the core package 5 while avoiding interference from other components during processing, ultimately achieving the goals of enhanced heat dissipation, convenient maintenance, structural stability, and operational safety. It is worth noting that during the winding of the core package 5, adhesive is applied above the winding start point and below the winding end point. After adhesive bonding and shaping, the hollow metal tube 1 is removed from the core package 5 to ensure structural stability and prevent loosening from affecting subsequent processes.

[0043] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An enhanced heat dissipating box capacitor, characterized by, include: A hollow metal tube (1) has multiple heat dissipation ribs (2) arranged in a circumferential ring on its outer wall. The lower end of the heat dissipation ribs (2) penetrates into the hollow metal tube (1) and is provided with a limiting plate (3). A connecting rod (4) is provided inside the hollow metal tube (1). The connecting rod (4) abuts against each limiting plate (3) to support the heat dissipation ribs (2). The core package (5) is formed by overlapping and winding aluminum foil and polypropylene film on the heat dissipation rib (2). Both ends of the core package (5) are coated with gold powder (15) and welded with lead wires (6). The inner surface, outer surface and the gold powder surfaces at both ends of the core package (5) are coated with insulating ceramic layer (16). The box body (7) is covered with a cover (8), the core package (5) is installed inside the box body (7), the two ends of the hollow metal tube (1) pass through to the outside of the box body (7) and the cover (8) respectively, the two ends of the heat dissipation rib (2) are pressed against the box body (7) and the cover (8) respectively, and the lead wire (6) passes through to the outside of the cover (8); The cross-sectional dimensions at both ends of the connecting rod (4) are smaller than the cross-sectional dimensions at the middle, forming a tapered guide section (9). The upper end of the heat dissipation rib (2) is provided with a support plate (13), and the top surface of the support plate (13) is provided with anti-slip texture. The contact surface between the core package (5) and the support plate (13) is coated with a thermally conductive silicone grease layer; The insulating ceramic layer (16) is alumina ceramic, aluminum nitride ceramic or beryllium oxide ceramic; the cover (8) is provided with a through hole (10) that matches the lead wire (6), the cover (8) is provided with a first mounting hole (11), the box body (7) is provided with a second mounting hole (12) on the side away from the cover (8), and the two ends of the hollow metal tube (1) are respectively adapted to the first mounting hole (11) and the second mounting hole (12).

2. The enhanced heat dissipation type box capacitor according to claim 1, wherein Rubber sleeves are provided on the inner sides of the through hole (10), the first mounting hole (11), and the second mounting hole (12).

3. The enhanced heat dissipation type box capacitor according to claim 1, wherein Both ends of the connecting rod (4) are detachably connected to several heat sinks (14).

4. The enhanced heat dissipation type box capacitor according to claim 1, characterized in that, An insulating sleeve is fitted on the outside of the lead wire (6).

5. A method for manufacturing an enhanced heat dissipation type box capacitor, comprising manufacturing an enhanced heat dissipation type box capacitor as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Insert the connecting rod (4) into the hollow metal tube (1) so that the outer wall of the connecting rod (4) presses against each limiting plate (3) and lifts up the heat dissipation ribs (2); S2. Aluminum foil and polypropylene raw film are overlapped and wound around the raised heat dissipation ribs (2) to form a core package (5). S3. Pull the connecting rod (4) out of the hollow metal tube (1) to loosen the heat dissipation ribs (2), and then remove the hollow metal tube (1) from the core package (5); S4. Spray gold coating (15) onto both ends of the core package (5) and solder the leads (6). S5. Spray an insulating ceramic layer (16) onto the inner surface, outer surface and gold-plated surfaces at both ends of the core package (5) after step S4. S6. After applying a thermally conductive silicone grease layer to the surface of the support plate (13), the hollow metal tube (1) is reinserted into the core package (5), and then the connecting rod (4) is reinserted into the hollow metal tube (1) so that the heat dissipation ribs (2) are supported and pressed against the inner wall of the core package (5). S7. Install the core package (5) inside the box (7) and seal the box (7) with the cover (8) to complete the assembly of the enhanced heat dissipation box capacitor.

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