DC support capacitor

Abstract

The utility model provides a DC support capacitor. The direct current support capacitor (100) comprises a core (1), a first busbar (2) and a heat conduction plate (3), the first busbar (2) comprises a plate-shaped first portion (21) and a plate-shaped second portion (22), the first portion (21) is electrically connected with a first end face (11) of the core (1), the second portion (22) extends in the height direction of the core (1) and is opposite to a side face (12) of the core (1), and the first portion (21) is electrically connected with a second end face (12) of the core (1). The second part (22) is arranged between the side surface (12) and the heat conducting plate (3), the plate surface of the second part (22) is parallel to the plate surface of the heat conducting plate (3), and the heat conducting plate (3) is used for transferring heat from the core (1) to the outside. According to the invention, the heat dissipation capability of the direct current support capacitor is improved by using the heat conduction characteristic of the direct current support capacitor in an economical manner.

Description

Technical Field

[0001] This disclosure relates to the field of capacitor heat dissipation, and more specifically, to a DC-supported capacitor. Background Technology

[0002] This section aims to provide background information relevant to understanding the various techniques described herein. As the title of this section implies, this is a discussion of related techniques that should in no way imply that they are necessarily prior art. Therefore, it should be understood that any statement in this section should be read in this context, rather than as an admission of any prior art.

[0003] DC-Link capacitors, also known as DC-Link capacitors or DC bus capacitors, are used to smooth and filter the output voltage, ensuring that voltage fluctuations on the DC bus remain within acceptable limits. They can also absorb high-amplitude pulsating currents and prevent the generation of high-amplitude pulsating voltages, thereby protecting the circuit from transient energy surges. They have high reliability and electrical performance.

[0004] In some technical solutions, the thermal conductivity of the DC-supported capacitor core is only 0.25 W / m·K in the X and Y directions and 0.8 W / m·K in the Z direction. In these designs, the Z-direction of the core is perpendicular to the aluminum plate surface. However, when the core film is very wide (i.e., the core height is relatively high), the capacitor size will be very large. Furthermore, the space occupied by the copper busbar solder joint structure reduces the heat dissipation area, leading to an increase in hot spot temperature. Utility Model Content

[0005] Depending on the specifics, the purpose of this disclosure is to improve the heat dissipation capacity of a DC-supported capacitor by utilizing its own thermal conductivity in an economical manner.

[0006] Furthermore, the purpose of this disclosure is to solve or at least alleviate one or more problems existing in the prior art.

[0007] This disclosure solves the above problems by providing a DC-supported capacitor. Specifically, according to one aspect of this disclosure, the following is provided:

[0008] A DC-supported capacitor includes a core, a first busbar, and a heat-conducting plate. The first busbar includes a first portion and a second portion configured as a plate. The first portion is electrically connected to a first end face of the core. The second portion extends along the height direction of the core and faces a side of the core. The second portion is disposed between the side face and the heat-conducting plate, and the plate surface of the second portion is parallel to the plate surface of the heat-conducting plate. The heat-conducting plate is used to transfer heat originating from the core to the outside.

[0009] Alternatively, according to one embodiment of this disclosure, the core is configured as a cylindrical structure with a circular, elliptical, or waist-shaped cross-section.

[0010] Optionally, according to one embodiment of this disclosure, the DC support capacitor includes an insulating member, which is disposed between the first busbar and the heat-conducting plate by hot pressing.

[0011] Optionally, according to one embodiment of the present disclosure, the DC support capacitor includes a second busbar, the second busbar including a third portion and a fourth portion configured as a plate, the third portion being electrically connected to a second end face of the core, and the fourth portion extending along the height direction of the core and opposite to the side face and disposed between the side face and the second portion.

[0012] Optionally, according to one embodiment of this disclosure, the first bus is configured with a flange connected to the second part, the flange is configured with a first pin, and the third part is configured with a second pin, the first pin and the second pin being used to connect to the positive and negative terminals of the IGBT, respectively.

[0013] Optionally, according to one embodiment of the present disclosure, the DC support capacitor includes a bracket with a mounting base, the first pin and the second pin being respectively connected to the IGBT via the mounting base, and the bracket also having an insulating plate electrically insulatingly disposed between the first pin and the second pin.

[0014] Optionally, according to one embodiment of the present disclosure, the first part has an opening structure and a solder joint structure formed within the opening structure, and the first end face is welded to the first part via the solder joint structure.

[0015] Optionally, according to one embodiment of the present disclosure, the insulating element is constructed as a sheet of insulating paper, the surface of which is parallel to and covers the plate surface of the second part.

[0016] Alternatively, according to one embodiment of this disclosure, a plurality of said cores are aligned and arranged along their thickness direction.

[0017] Alternatively, according to one embodiment of the present disclosure, the first busbar is configured as a copper busbar and the heat-conducting plate is configured as an aluminum plate. Attached Figure Description

[0018] Referring to the accompanying drawings, the above and other features of this disclosure will become apparent, wherein,

[0019] Figure 1 A perspective view of a DC-supported capacitor according to the present disclosure is shown;

[0020] Figure 2 A perspective view of the interior of a DC-supported capacitor according to the present disclosure is shown;

[0021] Figure 3 A side view of the interior of a DC-supported capacitor according to the present disclosure is shown;

[0022] Figure 4 A perspective view of the interior of a DC-supported capacitor according to the present disclosure, facing the second busbar, is shown.

[0023] Figure 5 A diagram showing the fit between a core, a first busbar, and a heat-conducting plate according to this disclosure is provided; and

[0024] Figure 6 A diagram showing the fit between a first busbar and a heat-conducting plate according to the present disclosure is provided. Detailed Implementation

[0025] It is readily understood that, based on the technical solutions of this disclosure, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this disclosure. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solutions of this disclosure and should not be considered as the entirety of this disclosure or as limitations or restrictions on the technical solutions of this disclosure.

[0026] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive. Furthermore, the terms "first," "second," "third," and similar expressions are used for descriptive and distinguishing purposes only and should not be construed as indicating or implying the relative importance of the corresponding components.

[0027] Figure 1 A perspective view of a DC-supported capacitor according to the present disclosure is shown; Figure 2 A perspective view of the interior of a DC-supported capacitor according to the present disclosure is shown; and Figure 3 A side view of the interior of a DC-supported capacitor according to the present disclosure is shown.

[0028] The DC-supported capacitor 100 includes a core 1, a first busbar 2, and a heat-conducting plate 3. The first busbar 2 includes a first part 21 and a second part 22 configured as a plate. The first part 21 is electrically connected to a first end face 11 of the core 1. The second part 22 extends along the height direction of the core 1 and is opposite to a side face 12 of the core 1. The second part 22 is disposed between the side face 12 and the heat-conducting plate 3, and the plate surface of the second part 22 is parallel to the plate surface of the heat-conducting plate 3. The heat-conducting plate 3 is used to transfer heat originating from the core 1 to the outside.

[0029] It should be understood that the core, as the main energy storage element of a DC-supported capacitor, provides stable voltage support, smooths current, and stores charge in the circuit to cope with current fluctuations and load changes. The core is sometimes also called the core body, battery cell, or core rod. During operation, the DC-supported capacitor, including the core, generates a large amount of heat, thus requiring heat dissipation. To protect the capacitor's components, the DC-supported capacitor also includes a housing 7, with most components housed inside the housing. The leads and connections, which will be explained later, extend to the outside of the housing.

[0030] For example, due to the characteristics of the core given by the manufacturing process, the thermal conductivity of the core in the Z direction (height direction, axial direction) is higher than that in the X and Y directions. Therefore, this technical solution utilizes the higher thermal conductivity in the Z direction to achieve heat transfer without the need to introduce other heat dissipation components, thus improving the heat dissipation effect while maintaining high cost performance.

[0031] Specifically, the first part of the first busbar forms an electrical connection at the first end face of the core, thus freeing up the entire size of the second part of the first busbar for heat transfer. The second part of the first busbar is positioned to extend along the height of the core and face the side of the core; in other words, the second part of the first busbar is parallel to the Z-direction of the core. This allows heat to be transferred to the dedicated heat transfer part of the first busbar using the high thermal conductivity of the core in the Z-direction. Furthermore, the surface of the second part is parallel to the surface of the heat-conducting plate, allowing heat to be transferred to the heat-conducting plate more efficiently, and ultimately to the outside (i.e., outside the DC-supported capacitor). Therefore, the thermal stability and lifespan of the capacitor are improved.

[0032] In addition, the area of ​​the second part and the heat-conducting plate can be made relatively large, which helps to achieve uniform heat dissipation from the core. By dispersing heat to the outside through their surface area, local overheating is avoided, thus improving the thermal management performance of the capacitor.

[0033] The core 1 can be constructed as a cylindrical structure with a circular, elliptical, or waist-shaped cross-section. The embodiment shown in the figure has a waist-shaped cross-section, where the waist shape can be understood as a rectangle with its shorter straight side modified into an arc. Thus, the cross-section of the cylindrical structure corresponds to the plane formed by the X and Y directions, and the stretching direction corresponds to the Z direction, or the height direction.

[0034] The manufacturing cost of the cross-sectional shape involved in this technical solution is controllable, which helps reduce obstacles in the current transmission process, improves current transmission efficiency, and also has higher mechanical strength, enabling it to better resist external impacts and vibrations. In particular, the waist-shaped cross-section facilitates the arrangement of multiple cores using its central rectangular portion, offering advantages in space utilization. Those skilled in the art can select core structures with different cross-sectional shapes according to actual needs; for example, in applications requiring higher power density, a waist-shaped column structure with a larger cross-section can be selected.

[0035] The DC-supported capacitor 100 includes an insulating component 4, which is disposed between the first busbar 2 and the heat-conducting plate 3 by hot pressing. It should be understood that the insulating component provides electrical insulation between the first busbar and the heat-conducting plate, ensuring that no electrical short circuit occurs between them. This technical solution specifically specifies that the insulating component is disposed by hot pressing, which further ensures the reliability and stability of the insulation effect, thereby improving the overall safety of the capacitor. It is also understood that the insulating component, while providing electrical insulation, also possesses certain thermal conductivity to effectively transfer heat from the first busbar to the heat-conducting plate. Hot pressing ensures good contact between the insulating component, the first busbar, and the heat-conducting plate, thereby improving heat transfer efficiency and helping to achieve a more uniform temperature distribution between the first busbar and the heat-conducting plate, reducing local overheating and extending the capacitor's service life. Finally, hot pressing enhances the mechanical stability of the entire capacitor structure, helping to resist external shocks and vibrations, ensuring stable operation of the capacitor in harsh environments, simplifying the assembly process, improving production efficiency, and facilitating subsequent maintenance and replacement. However, although not detailed in this disclosure, other arrangements, such as screw connections, snap-fit ​​connections, adhesive bonding, injection molding, and welding, can also be used.

[0036] It can also be seen that the insulating element 4 is constructed as a sheet of insulating paper, the surface of which is parallel to and covers the plate surface of the second part 22. In this way, the large surface area of ​​the insulating element is fully utilized to create efficient heat conduction between the first busbar and the heat-conducting plate, improving heat dissipation efficiency. On the other hand, the insulating paper has high dielectric strength, capable of withstanding high electric field strength without breakdown. Therefore, using insulating paper to construct the insulating element can significantly improve the insulation strength of the capacitor and enhance its resistance to electrical faults. In addition, insulating paper is low in cost, readily available and easy to maintain, and easy to process and shape. It can be easily cut into the required shape and size, exhibiting strong adaptability and compatibility with the busbars and heat-conducting plates it is matched with, thereby simplifying the capacitor manufacturing process and improving production efficiency.

[0037] In a test scheme based on this design, the entire busbar surface can participate in heat conduction with the heat-conducting plate, increasing the heat dissipation area by 33%. According to simulation results, the hot spot temperature decreased from 97℃ to 91℃, a 50% reduction in temperature rise. The hot spot temperature can be understood as the temperature of the hottest point in the capacitor or the highest point of the temperature distribution, typically reflecting the highest temperature level of the capacitor or that area under specific operating conditions. Therefore, excessively high hot spot temperatures can lead to performance degradation, shortened lifespan, or even capacitor damage. Controlling the hot spot temperature is therefore crucial for ensuring stable and reliable equipment operation. The simulation results show that by improving the design, the entire busbar surface can participate in heat conduction with the heat-conducting plate, effectively improving the equipment's heat dissipation performance and reducing the hot spot temperature, thereby contributing to improved equipment performance and lifespan.

[0038] Figure 4 A perspective view of the interior of a DC-supported capacitor according to the present disclosure, facing the second busbar, is shown.

[0039] The DC support capacitor 100 includes a second busbar 5, which includes a third part 51 and a fourth part 52 configured as a plate. The third part 51 is electrically connected to the second end face 13 of the core 1, and the fourth part 52 extends along the height direction of the core 1 and is opposite to the side face 12 and disposed between the side face 12 and the second part 22.

[0040] It should be understood that, in order to utilize the function of the capacitor, the first bus and the second bus can, for example, be connected to the positive and negative terminals of an external power source, respectively. For instance, the first bus could be connected to the positive terminal and the second bus to the negative terminal, or vice versa. Both types of buses utilize the end faces of the core to achieve electrical connection, thus allowing the Z-direction, or side surface, of the core, which has a higher thermal conductivity, to be used for heat transfer, ensuring high heat dissipation capacity. It can also be seen that this design arranges the fourth part relatively centrally with the second part, fully utilizing the heat dissipation capacity of the core's side surface, and optionally transferring heat to the outside through the large heat dissipation surface area between the second part, the insulating component, and the heat-conducting plate.

[0041] In this regard, it is feasible for the first bus to further include a first connecting portion 25, which, for example, connects to the second portion and extends outward from the housing; and for the second bus to further include a second connecting portion 54, which, for example, connects to the third portion and extends outward from the housing, so as to be electrically connected to a DC power supply respectively. Depending on the actual layout or wiring requirements, the extension method of these two connecting portions is not particularly constrained; they can be provided with curved portions, bends, or other structures to provide greater adaptability, thereby allowing them to extend smoothly from the housing and simultaneously adapt to the port layout of the external power supply. It is also feasible to arrange a first insulator 8 between the two connecting portions for insulation reasons, for example, in the form of insulating paper, and to match the shape of the connecting portions. For example, the first insulator may also have a bending feature to provide more comprehensive electrical insulation between the first and second connecting portions.

[0042] Similarly, considering insulation, an additional insulating element, such as insulating paper as a second insulator 9, can be provided between the fourth and second parts. Furthermore, the extension lengths of the fourth and second parts can be selected according to actual needs. In this example, the second part extends along the entire height of the core, ensuring a large heat dissipation surface, while the fourth part has a shorter extension length, but still utilizes the larger heat dissipation area of ​​the second part to achieve heat conduction. This allows the capacitor to maintain a compact size while still achieving effective heat dissipation and current transmission. Additionally, the fourth part provides additional structural support to the capacitor to some extent, enhancing its mechanical stability.

[0043] Figure 5 A diagram showing the fit between a core, a first busbar, and a heat-conducting plate according to this disclosure is provided; and Figure 6 A diagram showing the fit between a first busbar and a heat-conducting plate according to the present disclosure is provided.

[0044] The first bus 2 is configured with a flange 23 connected to the second part 22. A first pin 24 is configured on the flange 23, and a second pin 53 is configured on the third part 51. The first pin 24 and the second pin 53 are respectively used to connect to the positive and negative terminals of the IGBT (Insulated Gate Bipolar Transistor).

[0045] Thus, this technical solution still does not affect the overall heat dissipation capacity of the capacitor. For example, the heat from the first pin can be transferred via the flange and the second part, and the heat from the second pin can be transferred via the third part, the third part, and the second part. Both can fully utilize the second part, which can be configured with a larger surface area, and optionally the insulating paper and heat-conducting plate, to release heat to the surrounding environment. Therefore, it is also possible to arrange both types of pins on one side of the capacitor, such as one side of the second end face of the core, and alternate them, so as to make full use of space and to centrally connect these two types of pins to the IGBT. Also, by way of example, one embodiment of this capacitor has six pins. Those skilled in the art can adjust the number and arrangement of the pins according to the actual connection situation, for example, to adapt to various types of IGBT modules. Furthermore, as mentioned at the beginning, the pins extend beyond the housing for external connection of the capacitor.

[0046] from Figure 4 It can also be seen that the DC support capacitor 100 includes a bracket 6, the bracket 6 has a fixing base 61, the first pin 24 and the second pin 53 can be connected to the IGBT via the fixing base 61 respectively, the bracket 6 also has an insulating plate 62, the insulating plate 62 is electrically insulatingly disposed between the first pin 24 and the second pin 53.

[0047] Therefore, the bracket design provides stable support for the connection between the pins and the IGBT, ensuring the stable position of the capacitor in the circuit and reducing the risk of loosening or detachment due to vibration or external forces. Specific connection methods include threaded connections, ensuring stable current and voltage transmission and reducing malfunctions caused by poor contact. For this purpose, the bracket's mounting base can be provided with internal threads for threaded connections, or the mounting base can be provided with a space to accommodate a nut, achieving connection through the nut's internal threads. Furthermore, also for insulation safety reasons, the bracket in this technical solution reliably insulates the first and second pins through an insulating plate design. Depending on the pin arrangement, the insulating plate may be arranged, for example, perpendicular to the pin plate surface.

[0048] The first part 21 has an opening structure 211 and a welding point structure 212 formed in the opening structure 211, and the first end face 11 is welded to the first part 21 via the welding point structure 212.

[0049] This technical solution, on the one hand, limits the connection between the first busbar and the core to welding, resulting in higher connection strength, the ability to withstand greater tensile and shear forces, and improved stability of the entire structure. Welding also simplifies the manufacturing process, reduces costs, and shortens the processing and assembly time of components. Simultaneously, the design of the weld point structure makes the welding process easier to control and automate, thereby improving production efficiency. On the other hand, since the weld point structure, including the opening structure, which occupies a certain space is constructed in the first part and connected to the first end face of the core, the second part of the first busbar no longer needs any weld points or opening structures. This allows the second part to function as a complete heat dissipation surface and exchange heat with the side of the core with a higher thermal conductivity. The second busbar and the second end face can also be designed to be welded in the same way.

[0050] Feasible approach is to construct the end face of the core as a gold-plated welding surface to ensure good contact between the core and the welding material, thereby improving welding quality. The gold layer has excellent electrical and thermal conductivity, ensuring uniform heat and current transfer during the welding process and preventing poor welding or incomplete soldering. Simultaneously, the gold layer also possesses good mechanical strength and wear resistance, enhancing the product's adaptability and reliability.

[0051] Combination Figure 5 It can be seen that aligning multiple cores 1 along their thickness direction achieves a more compact layout, thereby saving space. Especially when the core cross-section is waist-shaped, the rectangular shape in the middle of the waist can be used to arrange the cores side by side, which facilitates assembly, resulting in better compactness and integration, as well as better overall rigidity. In addition, after the cores are aligned, a continuous heat dissipation surface can be formed, thereby increasing the heat dissipation area and improving heat dissipation efficiency.

[0052] Regarding materials, for example, the first busbar 2 is constructed of copper, and the heat-conducting plate 3 is constructed of aluminum. Thus, the extremely low resistivity, good conductivity, and corrosion resistance of the copper busbar ensure minimal current loss during transmission, improving energy efficiency. The aluminum plate, with its excellent heat dissipation and mechanical strength, effectively improves the system's heat dissipation performance, preventing equipment failure or performance degradation due to overheating. Furthermore, aluminum contributes to lightweight design. In addition, the busbar can also be made of aluminum, stainless steel, polyphenylene sulfide (PPS) + glass fiber, tungsten, brass, etc.; the heat-conducting plate can also be made of aluminum alloy, stainless steel, graphite, microcrystalline glass, titanium alloy, ceramic, etc. Those skilled in the art can make reasonable material selections based on application requirements, performance requirements, cost budget, and the overall performance and reliability requirements of the capacitor.

[0053] It is also clear that the capacitors of the various embodiments of this disclosure can have a wide range of applications or targets, including new energy vehicles such as electric vehicles, charging piles, transformers, or various scenarios that require DC to AC conversion.

[0054] It should be understood that all the above preferred embodiments are exemplary and not restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of this disclosure should be within the legal protection scope of this disclosure.

Claims

1. A DC-supported capacitor (100), characterized in that, The DC-supported capacitor (100) includes a core (1), a first busbar (2) and a heat-conducting plate (3). The first busbar (2) includes a first part (21) and a second part (22) configured as a plate. The first part (21) is electrically connected to a first end face (11) of the core (1). The second part (22) extends along the height direction of the core (1) and is opposite to the side face (12) of the core (1). The second part (22) is disposed between the side face (12) and the heat-conducting plate (3) and the plate surface of the second part (22) is parallel to the plate surface of the heat-conducting plate (3). The heat-conducting plate (3) is used to transfer heat from the core (1) to the outside.

2. The DC-supported capacitor (100) according to claim 1, characterized in that, The core (1) is constructed as a cylindrical structure with a circular, elliptical, or waist-shaped cross-section.

3. The DC-supported capacitor (100) according to claim 1, characterized in that, The DC support capacitor (100) includes an insulating component (4), which is disposed between the first busbar (2) and the heat-conducting plate (3) by hot pressing.

4. The DC-supported capacitor (100) according to claim 1, characterized in that, The DC-supported capacitor (100) includes a second bus (5), which includes a third part (51) and a fourth part (52) configured as a plate. The third part (51) is electrically connected to the second end face (13) of the core (1), and the fourth part (52) extends along the height direction of the core (1) and is opposite to the side face (12) and disposed between the side face (12) and the second part (22).

5. The DC-supported capacitor (100) according to claim 4, characterized in that, The first bus (2) is configured with a flange (23) connected to the second part (22), the flange (23) is configured with a first pin (24), and the third part (51) is configured with a second pin (53). The first pin (24) and the second pin (53) are respectively used to connect to the positive and negative terminals of the IGBT.

6. The DC-supported capacitor (100) according to claim 5, characterized in that, The DC-supported capacitor (100) includes a bracket (6) having a mounting base (61), the first pin (24) and the second pin (53) being respectively connected to the IGBT via the mounting base (61), and the bracket (6) also having an insulating plate (62) electrically insulatingly disposed between the first pin (24) and the second pin (53).

7. The DC-supported capacitor (100) according to claim 1, characterized in that, The first part (21) has an opening structure (211) and a weld point structure (212) formed in the opening structure (211), and the first end face (11) is welded to the first part (21) via the weld point structure (212).

8. The DC-supported capacitor (100) according to claim 3, characterized in that, The insulating element (4) is constructed as a sheet of insulating paper, the surface of which is parallel to and covers the plate surface of the second part (22).

9. The DC-supported capacitor (100) according to claim 1, characterized in that, Multiple cores (1) are aligned along their thickness direction.

10. The DC-supported capacitor (100) according to claim 1, characterized in that, The first busbar (2) is constructed of copper, and the heat-conducting plate (3) is constructed of aluminum.

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