A high voltage capacitor resistant to breakdown

Abstract

The utility model relates to a kind of anti-breakdown high-voltage capacitor, belong to capacitor technical field.The anti-breakdown high-voltage capacitor, comprising: shell, the shell top is provided with sealing rubber plug;Core, setting in shell interior, and core is provided with the lead-out wire that extends to the sealing rubber plug above and penetrates sealing rubber plug;Wherein, the core includes anode foil and cathode foil, anode foil and cathode foil surface are provided with dielectric layer, anode foil, cathode foil and dielectric layer are rolled into cylindrical shape, from inside to outside form the laminated sequence structure of dielectric layer, anode foil, dielectric layer, cathode foil and dielectric layer, set up core, when high voltage is applied to capacitor, electric field is dispersed through the polypropylene film and ceramic coating of dielectric layer, and the high dielectric constant of ceramic coating can reduce local electric field intensity;Anode foil and cathode foil are both double-sidedly coated by dielectric layer, completely avoid the direct contact of pole plate edge, and the outermost dielectric layer is as additional insulating barrier, improve overall anti-breakdown capability.

Description

Technical Field

[0001] This utility model relates to the field of capacitor technology, and in particular to a breakdown-resistant high-voltage capacitor. Background Technology

[0002] An electrolytic capacitor is a type of capacitor. The metal foil (aluminum or tantalum) is the positive electrode, and the oxide film (aluminum oxide or tantalum pentoxide) in close contact with the metal is the dielectric. The cathode is composed of conductive material, electrolyte (which can be liquid or solid), and other materials. Because the electrolyte is the main component of the cathode, it is named an electrolytic capacitor. It is crucial that the positive and negative terminals of an electrolytic capacitor be connected correctly. Aluminum electrolytic capacitors can be classified into four types: leaded aluminum electrolytic capacitors; horn-shaped aluminum electrolytic capacitors; bolt-type aluminum electrolytic capacitors; and solid aluminum electrolytic capacitors.

[0003] With the increasing voltage levels of power systems and the rapid development of new energy power generation, higher requirements are being placed on the withstand voltage and reliability of high-voltage capacitors. Currently, mainstream high-voltage capacitors adopt metallized film or oil-impregnated paper dielectric structures, and their withstand voltage ratings are typically between 10kV and 100kV. However, with the increase in voltage levels, the risk of dielectric breakdown in capacitors increases significantly, especially in high-frequency, high-temperature, or strong electric field environments, where the insulation performance of the dielectric material will further deteriorate, leading to capacitor failure or even explosion. Utility Model Content

[0004] Therefore, it is necessary to provide a breakdown-resistant high-voltage capacitor to address the problem that the insulation performance of dielectric materials will further deteriorate under high-frequency, high-temperature, or strong electric field environments, leading to capacitor failure or even explosion.

[0005] A breakdown-resistant high-voltage capacitor includes: a housing with a sealing plug at the top; a core disposed inside the housing, with a lead wire extending through the sealing plug and above it; wherein the core includes an anode foil and a cathode foil, the surfaces of the anode foil and cathode foil are provided with a dielectric layer, and the anode foil, cathode foil and dielectric layer are rolled into a cylindrical shape, forming a stacked structure of dielectric layer, anode foil, dielectric layer, cathode foil and dielectric layer from the inside out.

[0006] In one embodiment, a buffer layer is fixedly connected to the inner wall of the outer shell, and the buffer layer is disposed between the core and the outer shell.

[0007] In one embodiment, the buffer layer is configured as a porous silicone rubber material.

[0008] In one embodiment, the dielectric layer is configured as a composite material of a polypropylene film and a ceramic coating.

[0009] In one embodiment, insulating terminals are provided inside the housing at both ends of the core.

[0010] In one embodiment, pressure equalization rings are provided at both ends of the core.

[0011] In one embodiment, the inner wall of the housing is coated with a conductive coating.

[0012] In one embodiment, the conductive coating is fluorine-doped tin oxide, and a silicon dioxide insulating layer is provided between it and the inner wall of the outer casing.

[0013] Beneficial effects A core is incorporated so that when high voltage is applied to the capacitor, the electric field is dispersed through the polypropylene film and ceramic coating of the dielectric layer. The high dielectric constant of the ceramic coating can reduce the local electric field intensity. Both the anode foil and the cathode foil are double-sided covered by the dielectric layer, which completely avoids direct contact between the edges of the plates. The outermost dielectric layer acts as an additional insulating barrier to improve the overall breakdown resistance. The porous structure of the buffer layer absorbs the stress generated by the thermal expansion of the electrode assembly, preventing the dielectric layer from cracking; the metal structure of the outer shell provides electromagnetic shielding and mechanical protection. An equalizing ring is incorporated to further disperse the edge electric field; the inner wall of the outer shell is coated with a conductive coating to enhance the electromagnetic shielding effect. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is an exploded view of the present invention; Figure 3 This is a partial cross-sectional view of the structure of this utility model; Figure 4 This is a schematic diagram of the unfolded structure of the core of this utility model; Figure 5 This is a schematic diagram of the internal structure of the outer shell of this utility model.

[0016] Figure label: 100. Outer casing; 110. Lead wire; 120. Sealing plug; 200. Core; 210. Anode foil; 220. Cathode foil; 230. Dielectric layer; 240. Buffer layer; 250. Insulating terminal. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0018] The following is combined with Figures 1-5 This invention describes a breakdown-resistant high-voltage capacitor.

[0019] In one embodiment, a breakdown-resistant high-voltage capacitor includes: a housing 100, with a sealing plug 120 disposed on the top of the housing 100; a core 200 disposed inside the housing 100, and having a lead wire 110 extending through the sealing plug 120 and above the sealing plug 120; wherein the core 200 includes an anode foil 210 and a cathode foil 220, with a dielectric layer 230 disposed on the surfaces of the anode foil 210 and the cathode foil 220, and the anode foil 210, the cathode foil 220 and the dielectric layer 230 rolled into a cylindrical shape, forming a stacked structure of dielectric layer 230, anode foil 210, dielectric layer 230, cathode foil 220 and dielectric layer 230 from the inside out.

[0020] like Figure 2 , Figure 3 and Figure 4 As shown, the dielectric layer 230 is a composite material of polypropylene film and ceramic coating. Voltage equalization rings are provided at both ends of the core 200. The inner wall of the outer shell 100 is coated with a conductive coating. The conductive coating is fluorine-doped tin oxide, and a silicon dioxide insulating layer is provided between it and the inner wall of the outer shell 100.

[0021] In this embodiment, the outer shell 100 is a metal cylindrical shell with a roughened inner wall after sandblasting to improve adhesion. The sealing plug 120 is made of butyl rubber and has two built-in O-rings for fluororubber sealing to improve sealing performance. The lead wire 110 is a nickel-plated copper-clad steel wire, which is laser-welded to the outer shell 100 and then connected to a silicone insulating sleeve after passing through the plug. A silicon dioxide insulating layer is provided between the conductive coating and the inner wall of the outer shell 100. This prevents short circuits between the metal body of the outer shell 100 and the internal conductive coating or affects the electric field distribution. The winding structure of the core 200 is as follows: the innermost dielectric layer 230; the second innermost layer: the anode foil 210 covering the inner dielectric layer; the third innermost layer: the dielectric layer 230 covering the anode foil 210; the fourth innermost layer: the cathode foil 220 covering the third dielectric layer; and the outermost layer: the dielectric layer 230 covering the cathode foil 220. A symmetrical, wound structure is formed, with the electrode foils wrapped by a dielectric layer 230. Both the innermost and outermost layers are dielectric layers 230, and each electrode foil (anode and cathode) is wrapped by its own dielectric layer 230. This helps improve the electric field distribution, reduce edge effects, and enhance breakdown resistance. The polypropylene film provides excellent dielectric strength, low loss, and good self-healing properties. A ceramic coating, applied to the PP film, significantly improves the film's high-temperature resistance, mechanical strength, thermal conductivity, and corona resistance, thereby greatly enhancing the overall withstand voltage and breakdown resistance. Equalizing rings are located at both ends of the core 200. Their function is to improve the electric field distribution at the ends of the core 200, preventing excessively high field strength at the ends from causing partial discharge or breakdown. Fluorine-doped tin oxide is a transparent conductive oxide with good conductivity. Coating the inner wall of the outer casing 100 with an FTO layer forms an equipotential shielding layer, which effectively shields external interference, making the electric field environment of the core 200 more uniform and preventing abnormal discharge caused by stray capacitance or potential difference between the outer casing 100 and the core 200. A silicon dioxide insulating layer is also provided. With this insulating layer, the FTO coating can be independently connected to the required potential, thereby precisely controlling the electric field environment inside the outer casing 100. This avoids the unevenness caused by the metal outer casing 100 directly participating in the electric field distribution, greatly improving breakdown reliability.

[0022] It's important to note that capacitors are one of the most fundamental energy storage components in electronic circuits, their core principle being electrostatic energy storage. The simplest capacitor consists of two parallel metal plates and an insulating medium (such as air, ceramic, plastic film, or oxide layer) between them. Plates: Conductors (such as aluminum or tantalum) that carry charge. Medium: An insulator that prevents direct charge flow but allows electric field penetration. When a power source is connected to the plates, the positive plate accumulates positive charge, and the negative plate accumulates an equal amount of negative charge. The charge forms an electrostatic field across the medium, storing electrical energy in the form of this electric field. Capacitors can be charged and discharged. During charging, when the power source is connected, electrons flow from the positive plate to the power source (the positive plate becomes positively charged due to a lack of electrons, and the negative plate becomes negatively charged due to an excess of electrons), and the voltage gradually increases to the power source voltage. During discharging, the power source is disconnected and a load is connected; charge flows through the load, and the electric field energy is converted into other forms of energy (such as light or heat).

[0023] like Figure 1 , Figure 3 and Figure 5 As shown, a buffer layer 240 is fixedly connected to the inner wall of the outer shell 100, and the buffer layer 240 is disposed between the core 200 and the outer shell 100. The buffer layer 240 is made of porous silicone rubber material. Insulating terminals 250 are disposed inside the outer shell 100 at both ends of the core 200.

[0024] In this embodiment, the porous structure of the buffer layer 240 endows it with excellent elasticity and compressibility, absorbing mechanical stress generated by temperature changes or external vibrations in the core 200, and preventing damage caused by direct collision between the core 200 and the rigid outer shell 100. Filling the gap between the outer shell 100 and the core 200 ensures uniform pressure distribution, preventing localized stress concentration from damaging the brittle dielectric layer 230. As an insulating material, it further isolates the core 200 from the conductive coating on the inner wall of the outer shell 100, enhancing safety. Insulating terminals 250 are disposed inside the outer shell 100 and located at both axial ends of the core 200. They physically isolate the ends of the core 200 from the metal outer shell 100, preventing high-voltage areas at the ends from discharging to the outer shell 100. In conjunction with the buffer layer 240, they fix the core 200 axially, restricting its movement and forming axial fixation and insulation.

[0025] Working principle: The anode foil 210 is connected to a high potential, and the cathode foil 220 is connected to a low potential, forming a polarized electric field on both sides of the dielectric layer 230. The polypropylene matrix provides high dielectric strength, and the ceramic coating suppresses partial discharge. The symmetrical wrapping configuration of the dielectric layer 230 makes the electric field parallel to the foil surface, and the equalizing ring forces the electric field at the ends to be distributed radially, reducing the peak value of the edge field strength, improving the breakdown resistance, and facilitating use under high voltage.

[0026] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A breakdown-resistant high-voltage capacitor, characterized in that, include: The outer casing (100) has a sealing plug (120) on its top. The core (200) is disposed inside the outer shell (100), and the core (200) is provided with a lead wire (110) that penetrates the sealing plug (120) and extends to the top of the sealing plug (120). The core (200) includes an anode foil (210) and a cathode foil (220). A dielectric layer (230) is disposed on the surface of the anode foil (210) and the cathode foil (220). The anode foil (210), the cathode foil (220) and the dielectric layer (230) are rolled into a cylindrical shape, forming a stacked structure of dielectric layer (230), anode foil (210), dielectric layer (230), cathode foil (220) and dielectric layer (230) from the inside to the outside.

2. The breakdown-resistant high-voltage capacitor according to claim 1, characterized in that, A buffer layer (240) is fixedly connected to the inner wall of the outer shell (100), and the buffer layer (240) is disposed between the core (200) and the outer shell (100).

3. The breakdown-resistant high-voltage capacitor according to claim 2, characterized in that, The buffer layer (240) is made of porous silicone rubber material.

4. The breakdown-resistant high-voltage capacitor according to claim 1, characterized in that, The dielectric layer (230) is made of a composite material of polypropylene film and ceramic coating.

5. The breakdown-resistant high-voltage capacitor according to claim 1, characterized in that, The outer casing (100) has insulating terminals (250) located at both ends of the core (200) inside.

6. The breakdown-resistant high-voltage capacitor according to claim 1, characterized in that, The core (200) is provided with equalizing rings at both ends.

7. The breakdown-resistant high-voltage capacitor according to claim 1, characterized in that, The inner wall of the outer casing (100) is coated with a conductive coating.

8. The breakdown-resistant high-voltage capacitor according to claim 7, characterized in that, The conductive coating is fluorine-doped tin oxide, and a silicon dioxide insulating layer is provided between it and the inner wall of the outer shell (100).

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