capacitor

Abstract

The application discloses a capacitor, which comprises a plastic shell body, a metal water passing part and a filling material; the shell body is provided with a containing cavity for containing internal elements of the capacitor, and the containing cavity is provided with an upper opening; the water passing part is embedded in the shell body and located at the upper opening of the containing cavity; the water passing part is internally provided with a water channel for the circulation of cooling medium; the filling material is filled in the containing cavity and wraps at least part of the surface of the internal elements; and the filling material is in thermal conduction contact with the water passing part to transfer the heat of the internal elements to the water passing part. The shell body of the application is made of plastic material, and the water passing part made of metal material is used as the water channel part, which greatly reduces the material cost and product weight compared with the traditional aluminum shell scheme; meanwhile, the water passing part made of metal material has excellent high-temperature deformation resistance, which can ensure the size precision and sealing performance of the water channel and overcome the defect that the traditional plastic shell cannot integrate the heat dissipation water channel due to easy deformation at high temperature.

Description

Technical Field

[0001] This invention belongs to the field of capacitor technology, and specifically refers to a capacitor that combines an aluminum water channel with a plastic shell. Background Technology

[0002] With the rapid development of new energy vehicles, film capacitors with low self-inductance and self-healing properties have become the preferred choice for automotive capacitors. As companies increasingly demand higher space utilization efficiency in electric drive control systems, the integration requirements for capacitors are also increasing, while cost control is becoming more stringent.

[0003] Currently, there are two main technical solutions for the housing design of automotive film capacitors: (a) Traditional plastic shell encapsulation solutions Traditional plastic-encapsulated designs use plastic shells, offering advantages such as low material cost and lightweight products. However, plastic has a low thermal conductivity and poor heat dissipation efficiency, making it difficult to meet the heat dissipation requirements of capacitors under high-heat operating conditions. Furthermore, because the cooling channels of power modules require high dimensional accuracy and sealing performance, and plastic materials are prone to deformation at high temperatures, traditional plastic shells cannot meet the structural design requirements for integrated cooling channels.

[0004] (II) Traditional aluminum shell solution Traditional aluminum casing designs can integrate the heat dissipation channels of the power module, relying on the high thermal conductivity of aluminum to achieve excellent heat dissipation performance. However, the aluminum casing solution has the following drawbacks: First, aluminum is expensive and the product is heavy; second, because the aluminum casing is conductive, additional insulation design is required between the positive and negative electrodes and the casing, which not only increases material costs but also increases the difficulty of assembly in the workshop.

[0005] In summary, the existing technology lacks a capacitor housing design that can take into account the advantages of low cost and lightweight plastic housings while also meeting the requirements of high precision, high sealing performance, and excellent heat dissipation performance of the cooling channels. Summary of the Invention

[0006] The main objective of this invention is to provide a capacitor that combines the advantages of low cost and lightweight plastic shell with the requirements of high precision, high sealing performance and excellent heat dissipation performance of the heat dissipation channel.

[0007] To achieve the above objectives, the solution of the present invention is: A capacitor includes a plastic casing, a metal water-passing component, and a potting material. The casing has a cavity for accommodating internal components of the capacitor, and the cavity has an upper opening. The water-passing component is embedded in the casing and located at the upper opening of the cavity. The water-passing component has a water channel for the flow of a cooling medium. The potting material fills the cavity and covers at least a portion of the surface of the internal components. The potting material is in thermal conductive contact with the water-passing component to transfer heat from the internal components to the water-passing component.

[0008] After adopting the above technical solution, the present invention has the following technical effects: The outer shell of this invention is made of plastic, while the water channel is constructed using a metal water-passing component. This significantly reduces material costs and product weight compared to traditional aluminum shell designs. Furthermore, the metal water-passing component possesses excellent high-temperature deformation resistance, ensuring dimensional accuracy and sealing performance of the water channel. This overcomes the shortcomings of traditional plastic shells, which are prone to deformation at high temperatures and cannot integrate heat dissipation channels. The potting material makes thermal conductive contact with the water-passing component, allowing heat from internal components to be directly transferred to the component and carried away by the cooling medium. This achieves direct heat dissipation of the capacitor's internal components, meeting the technical requirements of high-heat operation. Moreover, since only the water-passing component is metal, only insulation design needs to be added at its corresponding location to meet the requirements. Compared to traditional aluminum shells, which require insulation design for all internal components, this greatly reduces insulation design costs and assembly difficulty in the workshop.

[0009] In a preferred embodiment, the water-passing component is integrally formed with the outer shell body using a secondary injection molding process.

[0010] Furthermore, at least one side of the water-passing component is provided with a skirt, and the skirt has a plurality of through-holes extending vertically; the skirt is embedded in the upper opening sidewall of the cavity, and injection molding material passes through the through-holes to anchor the water-passing component to the outer shell body. This makes the connection between the water-passing component and the outer shell body more secure, improving the overall strength of the product.

[0011] In a preferred embodiment, the water-passing component is made of aluminum and formed using a die-casting process. The advantages of using die-casting are that it significantly reduces product weight; simultaneously, the die-cast component has high strength, meeting the load-bearing and protective requirements of the capacitor casing.

[0012] Furthermore, the water-passing component is provided with an inlet and an outlet at both ends, and at least one medium flow groove is formed on the side surface of the water-passing component facing away from the cavity. The inlet and the outlet are respectively connected to the two ends of the medium flow groove. The groove opening of the medium flow groove is used for sealing and docking with the wall surface of the external equipment.

[0013] Furthermore, the medium flow channel is provided in multiple parts, and a connecting channel is formed between adjacent medium flow channels. A sealing plate is covered at the opening of the connecting channel, and the sealing plate can be connected to the opening of the connecting channel by friction welding to prevent the cooling medium from leaking from the connecting channel. This allows for the splicing of multiple medium flow channels to match the die-casting manufacturing process.

[0014] In a preferred embodiment, at least one layer of first insulating material is provided between the internal component and the water-passing component.

[0015] In a preferred embodiment, the internal components include at least a capacitor core, a first busbar, a second busbar, and a second insulating material; the capacitor core is disposed within the cavity; the first busbar and the second busbar are electrically connected to the two poles of the capacitor core, and respectively lead out a first terminal and a second terminal to the outside of the outer casing; the second insulating material is disposed on the first busbar and the second busbar to electrically isolate them.

[0016] Furthermore, the capacitor also includes a PCB board with a filter capacitor, the PCB board being fixedly mounted on the surface of the housing body and connected to the first terminal and the second terminal.

[0017] In a preferred embodiment, the cavity has a lower opening, which is sealed by a sealing plate made of plastic.

[0018] In the preferred technical solution, both the first insulating material and the second insulating material can be polyethylene terephthalate film, polypropylene film, or other insulating paper, selected according to the actual insulation requirements. The first insulating material can also be an elastic insulating material of thermally conductive insulating potting compound, which can further improve the heat conduction efficiency while achieving insulation isolation. The potting material can be epoxy resin. Attached Figure Description

[0019] Figure 1 Three-dimensional representation of a specific embodiment of the present invention Figure 1 .

[0020] Figure 2 Three-dimensional representation of a specific embodiment of the present invention Figure 2 .

[0021] Figure 3 This is an exploded view of a specific embodiment of the present invention.

[0022] Figure 4 This is a cross-sectional view and a schematic diagram of the cooling medium flow in a specific embodiment of the present invention.

[0023] Explanation of icon numbers: 10-Outer shell body; 11-Cavity; 12-Upper opening; 13-Lower opening; 20-Water passage component; 21-Water channel; 22-Skirt; 23-Material passage hole; 24-Inlet; 25-Outlet; 26-Medium flow channel; 27-Connecting channel; 30-Potting material; 40-Sealing plate; 50-First insulating material; 60-Capacitor core; 70-First busbar; 71-First terminal; 80-Second busbar; 81-Second terminal; 90-Second insulating material; 100-Sealing plate; 200-PCB board. Detailed Implementation

[0024] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0025] like Figures 1 to 4 As shown, this invention provides a capacitor, mainly comprising a plastic outer casing 10, a metal water-passing component 20, and a potting material 30. The outer casing 10 is manufactured using injection molding and has an internal cavity 11 for accommodating the capacitor's internal components. The upper and lower surfaces of the cavity 11 have an upper opening 12 and a lower opening 13, respectively. The lower opening 13 is sealed by a sealing plate 100, also made of plastic, which can be sealed to the lower end of the outer casing 10 by hot-melt welding or ultrasonic welding to ensure the sealing of the bottom of the cavity 11.

[0026] The water-passing component 20 is embedded within the outer shell body 10 and located at the upper opening 12 of the cavity 11. In this embodiment, the water-passing component 20 is made of aluminum and formed by die casting to achieve both lightweight and high strength. The interior of the water-passing component 20 has water channels 21 for the flow of cooling media (such as water or ethylene glycol coolant). To firmly bond the water-passing component 20 to the outer shell body 10, this embodiment employs a secondary injection molding process to integrally form the water-passing component 20 and the outer shell body 10. Specifically, at least one side of the water-passing component 20 has a protruding skirt 22, and the skirt 22 has several through-holes 23. During secondary injection molding, the skirt 22 is embedded in the side wall of the upper opening 12 of the cavity 11. Molten plastic material passes through the through-holes 23, and after cooling and solidification, it anchors the water-passing component 20 into the outer shell body 10, forming a reliable mechanical locking structure, thereby effectively preventing the water-passing component 20 from loosening or detaching during long-term use or under heated conditions.

[0027] The internal components of the capacitor mainly include a capacitor core 60, a first busbar 70, a second busbar 80, and a second insulating material 90. The capacitor core 60 is disposed within the capacitor cavity 11. The first busbar 70 and the second busbar 80 are electrically connected to the two poles of the capacitor core 60 by welding or crimping, and respectively extend to the outside of the outer casing 10 via first terminals 71 and second terminals 81 for connecting to external circuits. The second insulating material 90 is disposed between the first busbar 70 and the second busbar 80 to electrically isolate them and prevent short circuits. The second insulating material 90 can be made of polyethylene terephthalate film or polypropylene film, with the thickness selected according to the voltage resistance requirements. Furthermore, at least one layer of first insulating material 50 (shown as one layer in the figure) is disposed between the internal components and the water-passing component 20. The first insulating material 50 can also be made of polyethylene terephthalate film, polypropylene film, or a thermally conductive insulating potting compound, and its function is to minimize thermal resistance while ensuring electrical insulation, facilitating heat conduction.

[0028] The potting material 30 fills the cavity 11 and covers at least part (preferably all) of the surface of the internal components. The potting material 30 is typically an epoxy resin or polyurethane potting compound with good thermal conductivity, which forms a thermally conductive insulating layer after curing. The upper surface of the potting material 30 is in direct thermal conductive contact with the lower surface of the water-passing component 20 (or indirectly in contact through the first insulating material 50, but the first insulating material 50 is very thin and thermally conductive, therefore the overall thermal resistance is low). Figure 4 As shown, when the capacitor is working, the internal components (especially the capacitor core 60 and busbar) generate heat. This heat is first transferred to the potting material 30 in contact with it. Due to the good thermal conductivity of the potting material 30, the heat is rapidly conducted upwards to the bottom of the water-passing component 20. The water-passing component 20 is made of aluminum, which has extremely high thermal conductivity, and the heat is quickly transferred to the inner wall of the water channel 21. The cooling medium (such as...) Figure 4 (As indicated by the middle arrow) The water enters the water channel 21 from the inlet 24 at one end of the water passage 20, flows through the entire water channel 21, and is discharged from the outlet 25 at the other end. During this process, the cooling medium carries away the heat absorbed by the water passage 20, thereby achieving efficient heat dissipation.

[0029] Specifically, such as Figure 4As shown, at least one medium flow groove 26 is provided on the side of the water-passing component 20 facing away from the cavity 11 (i.e., the upper surface). This medium flow groove 26 is the main flow area of ​​the water channel 21. The inlet 24 and outlet 25 are respectively located at both ends of the water-passing component 20 and are connected to both ends of the medium flow groove 26. When the water-passing component 20 is installed and mated with external equipment (such as the housing of a power module or a medium circulation module), the groove opening of the medium flow groove 26 is sealed and connected to the wall of the external equipment to form a closed flow channel, and the cooling medium flows directionally within the groove. If multiple flow grooves are required to increase the heat dissipation area or to achieve a serpentine flow channel, a connecting groove 27 can be opened between adjacent medium flow grooves 26, so that the cooling medium flows through each groove sequentially. To prevent the cooling medium from leaking from the groove opening of the connecting groove 27, a sealing plate 40 is provided at the groove opening of the connecting groove 27. The sealing plate 40 and the groove opening of the connecting groove 27 are sealed by friction welding to ensure the complete airtightness of the flow channel. The inlet 24 and outlet 25 at both ends of the water-passing component 20 can be machined with threads or quick-connect structures for connection to external cooling pipes.

[0030] In this embodiment, the potting operation of the cavity 11 is performed after the water-passing component 20 and the outer shell body 10 are integrally formed. First, the internal components (including capacitor core 60, busbar and insulating material) are inserted into the cavity 11 through the lower opening 13. Then, the lower opening 13 is sealed with the sealing plate 100. Then, liquid potting material 30 is injected from the upper opening 12, which is not covered by the water-passing component 20, until the potting material 30 fills the cavity 11 and contacts the lower surface of the water-passing component 20, and then solidifies and forms the cavity.

[0031] In addition, the capacitor in this embodiment may also include a PCB board 200 with a filter capacitor. The PCB board 200 is fixedly mounted on the surface of the housing body 10 (for example, fixed above the water-passing component 20 or the housing body 10 by screws or clips) and connected to the first terminal 71 and the second terminal 81 to filter out high-frequency noise and improve electromagnetic compatibility performance.

[0032] Through the above structure, the present invention achieves an organic combination of the low cost and lightweight of the plastic shell and the high heat dissipation and high dimensional accuracy of the aluminum water-passing component. As an independent metal insert, the dimensional accuracy and sealing performance of the water channel 21 of the water-passing component 20 are guaranteed by the metal material and are not affected by the high-temperature deformation of the plastic. Simultaneously, since only the water-passing component 20 is a conductive metal, only the first insulating material 50 needs to be placed at this location to meet the insulation requirements. Compared with the all-aluminum shell solution, this significantly simplifies the insulation design and reduces assembly difficulty and material costs.

[0033] The above embodiments and figures are not intended to limit the product form and style of the present invention. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of the present invention.

Claims

1. A capacitor, characterized in that: It includes a plastic outer shell, metal water-passing parts, and potting material; The outer casing has a cavity for accommodating the internal components of the capacitor, and the cavity has an upper opening; The water-passing component is embedded in the outer shell and located at the upper opening of the cavity; the water-passing component is provided with water channels for the flow of cooling medium; The potting material fills the cavity and covers at least a portion of the surface of the internal component; the potting material makes thermal conductive contact with the water-passing component to transfer the heat of the internal component to the water-passing component.

2. The capacitor according to claim 1, characterized in that: The water-passing component is integrally formed with the outer shell body using a secondary injection molding process.

3. The capacitor according to claim 2, characterized in that: At least one side of the water-passing component is provided with a skirt, and the skirt is provided with a plurality of material passage holes that run vertically through it; the skirt is embedded in the upper opening sidewall of the cavity, and the injection molding material passes through the material passage holes to anchor the water-passing component to the outer shell body.

4. The capacitor according to claim 1, characterized in that: The water-passing component is made of aluminum and is formed by die casting.

5. The capacitor according to claim 4, characterized in that: The water-passing component has an inlet and an outlet at both ends, and at least one medium flow groove is formed on the side surface of the water-passing component facing away from the cavity. The inlet and the outlet are respectively connected to the two ends of the medium flow groove. The groove opening of the medium flow groove is used for sealing and docking with the wall surface of the external equipment.

6. The capacitor according to claim 5, characterized in that: The medium flow channel is provided in multiple ways, and a connecting channel is provided between adjacent medium flow channels. A sealing plate is provided at the opening of the connecting channel to prevent the cooling medium from leaking from the connecting channel.

7. The capacitor according to claim 1, characterized in that: At least one layer of first insulating material is provided between the internal components and the water-passing component.

8. The capacitor according to claim 1, characterized in that: The internal components include at least a capacitor core, a first busbar, a second busbar, and a second insulating material; the capacitor core is disposed within the cavity; the first busbar and the second busbar are electrically connected to the two poles of the capacitor core, and respectively lead out a first terminal and a second terminal to the outside of the outer casing; the second insulating material is disposed on the first busbar and the second busbar to electrically isolate them.

9. The capacitor according to claim 8, characterized in that: It also includes a PCB board with a filter capacitor, which is fixedly mounted on the surface of the housing body and connected to the first terminal and the second terminal.

10. The capacitor according to claim 1, characterized in that: The cavity has a lower opening, which is sealed by a sealing plate made of plastic.

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