Composite capacitor core shaft and capacitor element
By inserting a composite structure in which a thermally conductive metal body contacts a metallized film into the capacitor core, the heat dissipation and thermal balance problems of self-healing capacitor elements are solved, achieving more efficient heat conduction and a longer service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAN XD POWER CAPACITOR CO LTD
- Filing Date
- 2025-04-29
- Publication Date
- 2026-04-28
AI Technical Summary
Existing self-healing capacitor elements suffer from poor heat dissipation and thermal balance as their geometric dimensions increase, leading to localized overheating.
A composite capacitor core is adopted. A heat-conducting metal body is inserted into the annular elongated holes at both ends of the core body and comes into contact with the gold-plated layer of the metallized film to form a composite structure of insulator and heat-conducting metal body, ensuring safe insulation distance and effective heat transfer.
This improves the lateral thermal conductivity of the capacitor element, reduces the internal hot spot temperature, improves heat dissipation and thermal balance, and extends the life of the capacitor element.
Smart Images
Figure CN224177219U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of power capacitor manufacturing technology, specifically relating to a composite capacitor core and capacitor element. Background Technology
[0002] With the rapid development of domestic industry and agriculture, and the year-on-year increase in electricity consumption by enterprises, the demand for capacitors and the quality of capacitor products have also grown rapidly. Self-healing capacitors, due to their inherent self-healing properties, are widely used in various fields such as power, agriculture, and medicine to improve the power factor and power quality of the grid. The mandrel used in self-healing capacitors is an important basic component in the power industry and power electronics industry, and it is widely used in the winding of various high-voltage capacitor elements, medium- and low-voltage capacitor elements, and DC capacitor elements.
[0003] Currently, the internal heat of self-healing capacitor elements is mainly transferred to their surface through the polypropylene film. However, in actual operation, self-healing capacitor elements are affected by their own heat generation and heat radiation from surrounding elements. At this time, due to the slow thermal conductivity of the polypropylene film, the heat cannot be quickly transferred to the gold plating layer, resulting in localized overheating in the center and surrounding areas of the self-healing capacitor element.
[0004] The self-healing capacitor element uses a standardized cylindrical mandrel made primarily of engineering plastics. Inside is a hexagonal through-hole. During operation, a hexagonal guide rod of a winding machine passes through this through-hole, driving the mandrel to rotate and wind the self-healing capacitor element. In existing technologies, capacitor elements consist of a mandrel, a metallized film, and a gold-plated layer. As the geometric dimensions of capacitor elements increase, heat dissipation and internal thermal balance become bottlenecks. Utility Model Content
[0005] The purpose of this invention is to provide a composite capacitor core to solve the problems of heat dissipation and thermal balance deterioration inside capacitor elements with larger geometric dimensions in the prior art.
[0006] To solve the above problems, this utility model proposes a composite capacitor core shaft, and the technical solution adopted is as follows:
[0007] A composite capacitor mandrel includes a mandrel body with a regular hexagonal through hole. The mandrel body is composed of an insulator. Annular elongated holes are formed along the length of the mandrel body at both ends of its wall thickness. An insulator spacing is provided between the two adjacent ends of the two annular elongated holes to form an isolation. Thermally conductive metal bodies are inserted into the two annular elongated holes, and these thermally conductive metal bodies are integrally formed with the mandrel body. The ends of the two thermally conductive metal bodies furthest from each other are in contact with the gold-plated layers at both ends of the metallized film on a capacitor element prepared from the composite capacitor mandrel, thereby achieving heat transfer to the capacitor element. The insulator spacing is greater than the minimum creepage distance that can withstand the withstand voltage of the capacitor element, and the insulator spacing is adjustable according to the withstand voltage of the capacitor element. The temperature rise of the capacitor element prepared from the composite capacitor mandrel is reduced by 21.1%-23.4%.
[0008] Furthermore, the heat-conducting metal body is a cylindrical metal layer, which is inserted along the length direction of the annular elongated hole and cooperates with the annular elongated hole.
[0009] Furthermore, the thickness of the cylindrical metal layer is 0.5-0.6 mm.
[0010] Furthermore, the cylindrical metal layer is a cylindrical aluminum layer or a cylindrical copper layer.
[0011] Furthermore, each end of the cylindrical metal layer away from the others is provided with a boss, and both ends of the mandrel body are respectively fitted and installed with the bosses on the cylindrical metal layer.
[0012] Furthermore, the two annular elongated holes are symmetrically arranged at both ends of the mandrel body with respect to the center position of the mandrel body.
[0013] Furthermore, the insulator is an engineering plastic.
[0014] Furthermore, the melting point of the insulator is higher than the melting point of the metallization film on the capacitor element made from the composite capacitor core.
[0015] Furthermore, the internal hottest temperature of the capacitor element prepared by the composite capacitor mandrel is reduced by 4.6-5.1K.
[0016] This application also provides a capacitor element, including the aforementioned composite capacitor core.
[0017] Compared with the prior art, this application has the following beneficial effects:
[0018] This utility model is an improved utility model. It inserts heat-conducting metal bodies into annular elongated holes at both ends of the mandrel body. Simultaneously, an insulating gap is provided between the two adjacent ends of the two annular elongated holes to ensure the safe insulation of the heat-conducting metal bodies. This results in the mandrel body being composed of heat-conducting metal bodies and insulators, changing the original insulator structure to a composite structure of insulators and heat-conducting metal bodies. Furthermore, the ends of the two heat-conducting metal bodies furthest from each other contact the gold-plated layers at both ends of the metallized film on the capacitor element, thereby achieving heat transfer to the capacitor element. This effectively improves the lateral heat conduction efficiency of the capacitor element, reduces the internal hot spot temperature of the capacitor element, and thus improves the heat transfer effect, solving the problem of heat dissipation and deterioration of thermal balance inside capacitor elements with larger geometric dimensions. At the same time, the insulator gap ensures a safe insulating distance between the two heat-conducting metal bodies while maintaining sufficient heat transfer effect. The composite capacitor mandrel of this application has a simple structure and is particularly suitable for capacitor elements with larger diameters.
[0019] The heat-conducting metal body is a cylindrical metal layer inserted along the length of the annular elongated hole and fitting into the hole. This structure improves the stability of the composite capacitor core structure while further enhancing the heat transfer effect.
[0020] The cylindrical metal layer has a thickness of 0.5-0.6 mm. This structure can ensure both its own heat conduction area and the mechanical strength of the mandrel body. It is simple in structure and low in cost while ensuring heat transfer effect.
[0021] The cylindrical metal layer is either a cylindrical aluminum layer or a cylindrical copper layer, which is convenient for different application scenarios according to different needs.
[0022] Each cylindrical metal layer has a boss at one end away from the others. Both ends of the mandrel body are respectively fitted with the bosses on the cylindrical metal layer, which further improves the compatibility between the cylindrical metal layer and the mandrel body, as well as the structural stability of the composite capacitor mandrel.
[0023] The two annular elongated holes are symmetrically arranged at both ends of the mandrel body with respect to the center position of the mandrel body, which effectively prevents uneven heat transfer.
[0024] The melting point of the insulator is higher than that of the metallized film on the capacitor element made from the composite capacitor core, effectively preventing the insulator from melting first at high temperatures. Attached Figure Description
[0025] Figure 1 This is a cross-sectional view of the structure of a conventional mandrel in the existing technology;
[0026] Figure 2This is a cross-sectional view of the composite capacitor core of this utility model;
[0027] Figure 3 This is a schematic diagram of the structure of the composite capacitor core of this utility model;
[0028] Figure 4 This is a cross-sectional view of the engineering plastic structure of the composite capacitor core of this utility model;
[0029] Figure 5 This is a cross-sectional view of the aluminum component of the composite capacitor core of this utility model;
[0030] Figure 6 This is a schematic diagram of the structure of a capacitor element made from the composite capacitor core of this utility model.
[0031] Figure 7 This is a schematic diagram of the internal hot spot temperature values of a capacitor element manufactured using conventional mandrel processing techniques in the prior art;
[0032] Figure 8 This is a schematic diagram of the internal hot spot temperature values of the capacitor element made of a cylindrical aluminum layer in the composite capacitor core of this utility model.
[0033] Figure 9 This is a schematic diagram of the internal hot spot temperature values of the capacitor element made of a cylindrical copper layer in the composite capacitor core of this utility model.
[0034] In the diagram, 1. conventional mandrel, 2. cylindrical aluminum layer, 3. engineering plastic, 4. mandrel body, 5. metallized film, 6. gold spray layer. Detailed Implementation
[0035] As cited in the background art, in the prior art, the heat dissipation and thermal balance inside capacitor elements with larger geometric dimensions deteriorate. Therefore, this utility model provides a composite capacitor mandrel, including a mandrel body 4 with a regular hexagonal through hole. The mandrel body 4 is composed of an insulator for insulation. Annular elongated holes are formed along the length of the mandrel body 4 at both ends of its wall thickness. An insulator spacing is provided between the two adjacent ends of the two annular elongated holes to form an isolation. Thermally conductive metal bodies are inserted into the two annular elongated holes respectively, ensuring a safe insulating distance between the two thermally conductive metal bodies while effectively transferring heat. The thermally conductive metal bodies are integrally formed with the mandrel body 4 to prevent instability in the composite capacitor mandrel structure. The ends of the two thermally conductive metal bodies furthest from each other contact the gold-plated layers 6 at both ends of the metallized film 5 on the capacitor element made from the composite capacitor mandrel, thereby achieving heat transfer to the capacitor element. The composite capacitor core of this application consists of a thermally conductive metal body and an insulator. It replaces the original insulator structure with a composite structure of insulator and thermally conductive metal body. The ends of the two thermally conductive metal bodies furthest from each other contact the gold-plated layers 6 at both ends of the metallized film 5 on the capacitor element, thus achieving heat transfer within the capacitor element. The spacing between the insulators is greater than the minimum creepage distance that can withstand the withstand voltage of the capacitor element, and the spacing is adjustable according to the withstand voltage of the capacitor element. This ensures sufficient heat transfer while maintaining a safe insulating distance between the two thermally conductive metal bodies. As a result, the temperature rise of the capacitor element prepared using the composite capacitor core of this application is reduced by 21.1%-23.4%, effectively improving the lateral thermal conductivity of the capacitor element, reducing the internal hot spot temperature of the capacitor element, and thus improving the heat transfer effect. This solves the problem of heat dissipation and deteriorating thermal balance inside capacitor elements with larger geometric dimensions. The composite capacitor core of this application has a simple structure and is particularly suitable for capacitor elements with larger diameters.
[0036] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0038] The structure of a conventional mandrel 1 in the prior art is as follows: Figure 1 As shown. Specifically, the conventional mandrel 1 is typically a hollow cylinder made of a highly standardized insulating material (usually engineering plastic 3). Its outer surface is cylindrical, and its interior has a hexagonal through-hole. During use, the hexagonal through-rod of the winding machine passes through the hexagonal through-hole into the conventional mandrel 1 and drives the conventional mandrel 1 to rotate for winding the capacitor element. The conventional mandrel 1 is usually composed of only one type of insulating material. However, as the geometric dimensions of the capacitor element increase, heat dissipation and internal thermal balance become bottlenecks.
[0039] To address the problems existing in the prior art, this application provides a composite capacitor core.
[0040] Specific embodiment 1 of the composite capacitor mandrel of this utility model:
[0041] In this embodiment, as Figure 2 , Figure 3 and Figure 4 As shown, the device includes a mandrel body 4 with hexagonal through holes. The mandrel body 4 is composed of an insulator. Annular elongated holes are formed along the length of the mandrel body 4 at both ends of its wall thickness. An insulator spacing is provided between the two adjacent ends of the two annular elongated holes to form an isolation. Thermally conductive metal bodies are inserted into the two annular elongated holes, and these thermally conductive metal bodies are integrally formed with the mandrel body 4. The ends of the two thermally conductive metal bodies furthest from each other are in contact with the gold-plated layers 6 at both ends of the metallized film 5 on the capacitor element prepared by the composite capacitor mandrel, thereby achieving heat transfer to the capacitor element. Simultaneously, the insulator spacing is greater than the minimum creepage distance that can withstand the withstand voltage of the capacitor element prepared by the composite capacitor mandrel, and the insulator spacing is adjustable according to the withstand voltage of the capacitor element. The insulator is an engineering plastic 3. The temperature rise of the capacitor element prepared by the composite capacitor mandrel in this application is reduced by 21.1%-23.4%.
[0042] Specifically, in this embodiment, as Figure 5 As shown, the heat-conducting metal body is a cylindrical metal layer inserted along the length of the annular elongated hole and mating with it. Each cylindrical metal layer has a boss at its far end, and both ends of the mandrel body 4 are respectively fitted with these bosses. In use, the two cylindrical metal layers are inserted from both ends of the mandrel body 4 and fixedly engaged with each other by the bosses on the cylindrical metal layers, ensuring the stability of the mandrel body 4 structure and ensuring that the far ends of the two heat-conducting metal bodies are in contact with the gold-plated layers 6 at both ends of the metallized film 5 on the capacitor element. The cylindrical metal layer is a cylindrical aluminum layer 2. The thickness of the cylindrical metal layer is 0.5-0.6 mm.
[0043] In other embodiments, the cylindrical metal layer may be a cylindrical copper layer.
[0044] Specific embodiment 2 of the composite capacitor mandrel of this utility model:
[0045] Based on the above-described technical concept of this utility model, or based on the specific embodiments of this utility model described above, another embodiment is provided below.
[0046] In this embodiment, as Figure 2 As shown, two annular elongated holes are symmetrically arranged at both ends of the mandrel body 4 with respect to the center position of the mandrel body 4. At this time, the two annular elongated holes are symmetrically arranged at both ends of the mandrel body 4 with respect to the spacing between the insulators. The melting point of the insulator is higher than the melting point of the metallized film 5 on the capacitor element prepared from the composite capacitor mandrel.
[0047] In other embodiments, the two annular elongated holes may be asymmetrically positioned at both ends of the mandrel body 4 relative to the center position of the mandrel body 4.
[0048] Specifically, the processing method of the composite capacitor core shaft of this application is as follows: First, a cylindrical metal layer is prefabricated; second, engineering plastic 3 is heated and melted; then, the cylindrical metal layer is placed into a mold, and the molten engineering plastic 3 is injected into the mold; finally, demolding is performed to obtain a complete composite capacitor core shaft. At this time, the outermost ends of the composite capacitor core shaft contain a cylindrical metal layer, and the middle part is engineering plastic 3.
[0049] This utility model also provides a capacitor element, including the composite capacitor core described above.
[0050] The composite capacitor mandrel of this application is used to process capacitor elements. The processing of the capacitor element is as follows: after the metallized film 5 is wound onto the composite capacitor mandrel of this application to reach a certain diameter, a gold spraying process is performed on the cylindrical end faces of both ends of the composite capacitor mandrel of this application, so that each end face of the capacitor element forms a cylindrical electrode with a thickness of about 1 mm, i.e., a gold spraying layer 6, and then the capacitor element is obtained. Figure 6 As shown in the figure. The distance between the two end faces of the electroplated capacitor element is the same as the length of the composite capacitor core.
[0051] The performance of composite capacitor cores constructed from different thermally conductive metals is compared with that of conventional core 1, as follows:
[0052] A cylindrical aluminum layer 2 is used as the heat-conducting metal body. The conventional mandrel 1 and the composite capacitor mandrel of this invention have the same external dimensions. Assuming that the capacitor elements manufactured by both are identical in geometry, material, and structure except for the mandrel, and that the heating power of both capacitor elements is set to 0.46W, and the external dimensions of both capacitor elements are φ68mm×152mm, simulation software is used for calculation. The external temperature of the capacitor elements is set to 55℃, the circumferential surface of the capacitor elements is insulated, and heat dissipation is achieved only through air convection via the gold-plated layers 6 on both sides, with a convection coefficient of 5W / m. 2 .
[0053] At this point, the calculation results of the internal hot spot temperature diagram of the capacitor element using conventional mandrel 1 are as follows: Figure 7 As shown, the temperature of the hottest spot inside the capacitor element using the conventional mandrel 1 is 76.8℃, with a temperature rise of 21.8K relative to the surrounding environment. The calculated results for the hottest spot temperature inside the capacitor element using the composite capacitor mandrel of this invention are as follows: Figure 8 As shown, the internal hottest temperature is 72.2℃, with a temperature rise of 17.2K relative to the surrounding environment. Therefore, the temperature rise of the capacitor element using the composite capacitor core of this invention is reduced by 4.6K compared to the temperature rise of the capacitor element using the conventional core 1, representing a reduction of 21.1%.
[0054] A cylindrical copper layer is used as the heat-conducting metal body, while other design parameters remain consistent with those described above, where a cylindrical aluminum layer 2 is used as the heat-conducting metal body. The calculated hot spot temperature value inside the capacitor element using the composite capacitor core of this invention is as follows: Figure 9As shown, the internal hottest point temperature is 71.7℃, with a temperature rise of 16.7K relative to the surrounding environment. Therefore, the temperature rise of the capacitor element using the composite capacitor core of this invention is reduced by 5.1K compared to the temperature rise of the capacitor element using the conventional core 1, a reduction of 23.4%. This demonstrates that the heat transfer effect of using a cylindrical copper layer as the heat-conducting metal body is comparable to that of using a cylindrical aluminum layer 2 as the heat-conducting metal body, but aluminum has a lower density, which allows the composite capacitor core of this invention to have a smaller mass and lower cost.
[0055] In summary, during use, the internal hottest temperature of a capacitor element is directly related to its lifespan. For every 8-10K increase in the internal hottest temperature, the lifespan is reduced by half. The capacitor element manufactured using the composite capacitor core of this invention has a reduced internal hottest temperature of 4.6-5.1K, which is about half of the 8-10K temperature, and its lifespan is expected to double.
[0056] From the above description of the specific embodiments of the composite capacitor mandrel of this utility model, it can be seen that the composite capacitor mandrel of this utility model includes a mandrel body 4 with a regular hexagonal through hole. The mandrel body 4 is composed of an insulator for insulation. Annular elongated holes are formed along the length of the mandrel body 4 at both ends of its wall thickness. An insulator spacing is provided between the two ends of the two annular elongated holes that are close to each other to form an isolation. Thermally conductive metal bodies are inserted into the two annular elongated holes respectively, ensuring a safe insulating distance between the two thermally conductive metal bodies while effectively transferring heat. Furthermore, the thermally conductive metal bodies are integrally formed with the mandrel body 4 to prevent instability of the composite capacitor mandrel structure. The ends of the two thermally conductive metal bodies that are far from each other are in contact with the gold-plated layers 6 at both ends of the metallized film 5 on the capacitor element prepared by the composite capacitor mandrel, thereby achieving heat transfer of the capacitor element. The composite capacitor core of this application consists of a thermally conductive metal body and an insulator. It replaces the original insulator structure with a composite structure of insulator and thermally conductive metal body. The ends of the two thermally conductive metal bodies furthest from each other contact the gold-plated layers 6 at both ends of the metallized film 5 on the capacitor element, thus achieving heat transfer within the capacitor element. The spacing between the insulators is greater than the minimum creepage distance that can withstand the withstand voltage of the capacitor element, and the spacing is adjustable according to the withstand voltage of the capacitor element. This ensures sufficient heat transfer while maintaining a safe insulating distance between the two thermally conductive metal bodies. As a result, the temperature rise of the capacitor element prepared using the composite capacitor core of this application is reduced by 21.1%-23.4%, effectively improving the lateral thermal conductivity of the capacitor element, reducing the internal hot spot temperature of the capacitor element, and thus improving the heat transfer effect. This solves the problem of heat dissipation and deteriorating thermal balance inside capacitor elements with larger geometric dimensions. The composite capacitor core of this application has a simple structure and is particularly suitable for capacitor elements with larger diameters.
[0057] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. The patent protection scope of the present utility model shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present utility model shall also be included in the protection scope of the present utility model.
Claims
1. A composite capacitor core, characterized in that, The device includes a mandrel body (4) with a regular hexagonal through hole. The mandrel body (4) is composed of an insulator. Annular elongated holes are formed along the length of the mandrel body (4) at both ends of its wall thickness. An insulator spacing is provided between the two annular elongated holes that are close to each other to form an isolation. A heat-conducting metal body is inserted into each of the two annular elongated holes. The heat-conducting metal body is integrally formed with the mandrel body (4). The ends of the two heat-conducting metal bodies that are far from each other are in contact with the gold-plated layers (6) at both ends of the metallized film (5) on the capacitor element prepared by the composite capacitor mandrel, so as to realize heat transfer of the capacitor element. The insulator spacing is greater than the minimum creepage distance that can withstand the withstand voltage of the capacitor element, and the insulator spacing is adjustable according to the withstand voltage of the capacitor element. The temperature rise of the capacitor element prepared by the composite capacitor mandrel is reduced by 21.1%-23.4%.
2. The composite capacitor mandrel according to claim 1, characterized in that, The heat-conducting metal body is a cylindrical metal layer, which is inserted along the length of the annular elongated hole and matches the annular elongated hole.
3. The composite capacitor mandrel according to claim 2, characterized in that, The thickness of the cylindrical metal layer is 0.5-0.6 mm.
4. The composite capacitor mandrel according to claim 2, characterized in that, The cylindrical metal layer is a cylindrical aluminum layer (2) or a cylindrical copper layer.
5. The composite capacitor mandrel according to claim 2, characterized in that, Each of the cylindrical metal layers has a boss at one end away from the other, and the two ends of the mandrel body (4) are respectively fitted with the bosses on the cylindrical metal layer.
6. The composite capacitor mandrel according to claim 1, characterized in that, The two annular elongated holes are symmetrically arranged at both ends of the mandrel body (4) with respect to the center position of the mandrel body (4).
7. The composite capacitor mandrel according to claim 1, characterized in that, The insulator is an engineering plastic (3).
8. The composite capacitor mandrel according to claim 1, characterized in that, The melting point of the insulator is higher than that of the metallization film (5) on the capacitor element made from the composite capacitor core.
9. The composite capacitor mandrel according to claim 1, characterized in that, The internal hotspot temperature of the capacitor element made from the composite capacitor mandrel is reduced by 4.6-5.1K.
10. A capacitor element, characterized in that, Includes the composite capacitor core as described in any one of claims 1-9.