Manufacturing method of high-temperature-resistant filter capacitor and capacitor

Abstract

The invention discloses a manufacturing method of a high-temperature-resistant filter capacitor and the capacitor, and relates to the field of capacitor manufacturing, a square plastic shell, a group of metal electrodes and a metallized film are provided, the metallized film is clamped between the group of metal electrodes, and the group of metal electrodes are divided into a positive electrode plate and a negative electrode plate; winding a group of metal electrodes and a metallized film into a core, performing hot pressing process treatment on the core, putting the core into a square plastic shell, and encapsulating the metal electrodes and the metallized film wound in the square plastic shell with epoxy resin to form a finished product capacitor; according to the invention, the internal pressure of the capacitor is uniformly distributed through hot pressing, metal spraying is carried out after the polymerization of the film is ensured, and after processing and assembling, the capacitor core is put into the oven and baked under certain temperature and time conditions, so that the internal and external shrinkage of the capacitor core is ensured to be uniform, and through the optimization of hot pressing, bulk baking and other processes, the performance of the capacitor core is improved. The risk of failure of the capacitor at high temperature is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of capacitor manufacturing, and more specifically, to a manufacturing method of a high temperature resistant filter capacitor and a capacitor. Background Art

[0002] The main body of the capacitor is two conductors close to each other, with a layer of non-conductive insulating medium in between; when a voltage is applied between the two plates of the capacitor, the capacitor will store charge; the capacitance of the capacitor is numerically equal to the ratio of the voltage on one conductive plate to the voltage between the two plates. Capacitors play an important role in circuits such as tuning, bypassing, coupling, and filtering; Referring to the Chinese patent application with publication number CN114068725B, a PIP capacitor and a method for manufacturing the PIP capacitor are disclosed. Since the threshold voltage injection region has the same conductivity type as the source region and the drain region, and the threshold voltage injection region has a different conductivity type from the body region, the PIP capacitor has high capacitance efficiency and the operating voltage can be extended to a low voltage region, thereby meeting the needs of more circuits. However, the temperature resistance of capacitors in the prior art is mostly limited. The manufacturing process of conventional capacitors includes core manufacturing, core hot pressing, core drying, welding, packaging and other steps, but these processes are not specifically optimized for performance such as resistance to high temperatures of 125°C. In particular, for some specific application environments, traditional capacitors cannot meet the use requirements of some occasions, and they need to have long-term resistance to high temperatures of 125°C to meet the use requirements of specific occasions. At the same time, the prior art cannot provide protection when the leads of the capacitor are connected to the circuit. The connection of the leads will be affected by high temperature and moisture, affecting the service life of the capacitor. Summary of the invention

[0003] Most of the traditional capacitors in the prior art have limited temperature resistance. However, for some specific application environments, traditional capacitors cannot meet the use requirements of some occasions. They need to have long-term high temperature resistance to meet the use requirements of specific occasions. The purpose of the present invention is to provide a manufacturing method for a high-temperature resistant filter capacitor and a capacitor using high-quality materials and innovative processes, which significantly improves the high temperature performance and electrical performance of the capacitor and has broad application prospects and market value.

[0004] To solve the above problems, the present invention adopts the following technical solutions.

[0005] In a first aspect, an embodiment of the present application provides a method for manufacturing a high temperature resistant filter capacitor, comprising the following steps: S10, providing a square plastic shell, a group of metal electrodes and a metallized film, wherein the metallized film is sandwiched between the group of metal electrodes, the group of metal electrodes is divided into a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet are respectively connected with a first lead pin and a second lead pin, and the group of metal electrodes and the metallized film are wound; S20, subjecting the wound set of metal electrodes and metallized film to a hot pressing process; S30, spraying metal or metal alloy onto the surface of the square plastic shell and a group of metal electrodes through a gold spraying process; S40, providing an oven, and placing the metal electrode and the metallized film into the oven for thermal baking treatment; S50, placing the metal electrode and the metallized film into a square plastic shell, and then placing the square plastic shell in the center of a fixture of an energizing machine, ensuring that the capacitor is correctly placed, and then performing voltage energization and current energization on it; S60, providing a lead wire, welding the lead wire to the gold-sprayed surface on the square plastic shell, and connecting the first lead pin and the second lead pin to the lead wire; S70, providing potting material and epoxy resin, evacuating the square plastic shell to remove the internal air, filling the core and the inner wall of the square plastic shell with the potting material; potting the square plastic shell and the core with epoxy resin to obtain a finished capacitor.

[0006] Furthermore, the environmental conditions for the hot pressing process of the metal electrode and the metallized film are 7Mpa, 95°C, and 700s to 720s.

[0007] Furthermore, the environmental conditions for thermal baking in the oven are 1.5h×85°C+1.5h×95°C+2h×115°C+6h×130°C.

[0008] Furthermore, the material of the metallized film is polyimide (PI) and polyetheretherketone (PEEK).

[0009] Furthermore, the thickness of the metallized film is controlled between 1 μm and 10 μm.

[0010] Furthermore, the material of the metal electrode is aluminum or nickel-chromium alloy.

[0011] Furthermore, the finished capacitor is subjected to performance testing at high temperature to detect its capacitance, leakage current and withstand voltage performance at a temperature of 125° C. or above.

[0012] In a second aspect, an embodiment of the present application provides a capacitor, which is prepared according to a manufacturing method of a high temperature resistant filter capacitor, wherein the protection assembly comprises: a protection shell, a plurality of protection sleeves and a plurality of fastening hoses, wherein the protection shell is sleeved on one end of the square plastic shell connected to the lead wire, and the two ends of the plurality of protection sleeves are respectively coaxially arranged with the plurality of fastening hoses, and an installation cavity is arranged in the protection shell, and one end of the plurality of protection sleeves is arranged in the installation cavity; A worm gear is coaxially arranged on the fastening hose outside the protective sleeve arranged in the installation cavity. A worm is arranged in the installation cavity. The worm is meshed with multiple worm gears for transmission. A knob is arranged on the outer wall of the square plastic shell. The knob is coaxially fixedly connected with the worm.

[0013] Furthermore, the square plastic shell is provided as a rectangular hollow shell, a placement cavity is provided in the square plastic shell, and the wound metal electrode and metallized film are arranged in the installation cavity of the square plastic shell.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present application, within the first time after the core is manufactured, the core is subjected to hot pressing to evenly distribute the internal pressure of the capacitor, thereby improving its working performance and extending the service life of the capacitor; ensuring the polymerization of the film, and then spraying gold. After spraying gold, during the capacitor manufacturing process, after certain processing and assembly, the capacitor core is placed in an oven and baked under certain temperature and time conditions to ensure uniform shrinkage inside and outside the capacitor core, achieve the purpose of shaping, and avoid damage to the core. After process optimization such as hot pressing and bulk baking, the risk of capacitor failure at high temperature is reduced and the service life is extended.

[0015] (2) This application ensures the capacitance stability and leakage current control of the capacitor at high temperature and prolongs its service life by adopting high-temperature dielectric materials; effectively reduces the dielectric loss inside the capacitor by hot pressing, which is a key step to improve the efficiency of the capacitor, so that the pressure inside the capacitor is evenly distributed, which can not only improve its working performance but also prolong the service life of the capacitor. For high-voltage capacitors, hot pressing also helps to ensure the flatness of the electrode and eliminate stress, thereby improving the insulation strength of the capacitor; improve the stability and efficiency of the capacitor in the electronic circuit, thereby improving the reliability of the entire electronic device.

[0016] (3) The inner and outer electrodes of the capacitor in this application are made of high-temperature resistant metal materials to ensure good conductivity in high-temperature environments. These materials not only have good conductivity, but have also been specially treated to enhance corrosion resistance and prevent electrochemical reactions under extreme conditions.

[0017] (4) In this application, the high temperature resistant filter capacitor optimizes the material and structural design to cope with the challenges in high temperature environment, and has efficient energy storage and stable electrical performance, ensuring that the connection between the two will not fail at high temperature. The encapsulation layer not only protects the internal structure, but also ensures good sealing and oxidation resistance, preventing external factors from affecting the performance of the capacitor.

[0018] (5) In the present application, the protective shell is clamped on one end of the square plastic shell connected to the lead wire, and after fixed installation, after the lead wire is connected to the circuit, the fastening hose on the protective sleeve is pulled to cover the connection between the lead wire and the circuit, and the fastening hose at that location is heated and rotated, and then waited for natural cooling to stabilize; by rotating the knob, the worm drives a group of worm gears to rotate synchronously, thereby causing the fastening hose located in the installation cavity of the protective shell to rotate and contract to fix one end of the protective sleeve located in the installation cavity, thereby preventing the connection of the lead wire from being affected by high temperature and moisture, thereby ensuring the normal service life of the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the overall process of a method for manufacturing a high temperature resistant filter capacitor provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of the main working components of a high temperature resistant filter capacitor provided in an embodiment of the present application; Figure 3 A schematic diagram of the internal structure of a high temperature resistant filter capacitor provided in an embodiment of the present application; Figure 4 A schematic diagram of the installation structure of a high temperature resistant filter capacitor and a protection component provided in an embodiment of the present application; Figure 5 A schematic diagram of the internal structure of a protective shell of a high-temperature resistant filter capacitor provided in an embodiment of the present application.

[0020] Description of the numbers in the figure: 1. Square plastic shell; 2. Metal electrode; 21. Positive electrode sheet; 211. First lead pin; 22. Negative electrode sheet; 221. Second lead pin; 3. Metallized film; 4. Lead wire; 5. Potting material; 6. Epoxy resin; 7. Protective shell; 8. Protective sleeve; 9. Fastening hose; 10. Knob; 11. Worm; 12. Worm gear. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0022] Embodiment 1: See also Figures 1 to 5 , a method for manufacturing a high temperature resistant filter capacitor, comprising the following steps: S10, providing a plastic shell 1, a group of metal electrodes 2 and a metallized film 3, wherein the metallized film 3 is sandwiched between the group of metal electrodes 2, the group of metal electrodes 2 is divided into a positive electrode sheet 21 and a negative electrode sheet 22, the positive electrode sheet 21 and the negative electrode sheet 22 are respectively connected with a first lead pin 211 and a second lead pin 221, and the group of metal electrodes 2 and the metallized film 3 are wound; S20, subjecting the wound set of metal electrodes 2 and metallized film 3 to a hot pressing process; S30, spraying metal or metal alloy onto the surface of the square plastic shell 1 and a group of metal electrodes 2 by means of a gold spraying process; S40, providing an oven, placing the metal electrode 2 and the metallized film 3 in the oven for thermal baking treatment; S50, placing the metal electrode 2 and the metallized film 3 into the square plastic shell 1, and then placing the square plastic shell 1 in the center of the fixture of the energizing machine, ensuring that the capacitor is correctly placed, and then performing voltage energization and current energization on it; S60, providing a lead 4, welding the lead 4 to the gold-sprayed surface on the square plastic shell 1, and connecting the first lead pin 211 and the second lead pin 221 to the lead 4; S70, providing potting material 5 and epoxy resin 6, evacuating the square plastic shell 1 to remove the internal air, and filling the core and the inner wall of the square plastic shell 1 with the potting material 5; potting the square plastic shell 1 and the core with epoxy resin 6 to obtain a finished capacitor; By adopting the above technical solution, the core structure of the capacitor is a very thin metalized film 3 as a dielectric, sandwiched between two metal electrodes 2; so that the finished capacitor has good self-healing performance, high withstand voltage and large capacity, and at the same time, the volume is relatively small, which is very suitable for use in the circuit; The contact area of ​​the capacitor can be increased through the gold spraying process, and the reliability and stability of the connection can be improved. The spraying of metal or metal alloy can enhance the conductivity of the capacitor. The metal or metal alloy is directly sprayed on the surface of the capacitor in a vacuum environment by using thermal evaporation or electron beam physical deposition technology. After the gold spraying is completed, a layer of polishing varnish will be evenly sprayed to ensure the smoothness and corrosion resistance of the surface; thereby improving its storage capacity and discharge capacity; in addition, the gold spraying layer can also serve as a protective layer to prevent the capacitor from being damaged by external environments such as acid rain, oxidation, and corrosion, thereby extending the service life of the capacitor; By using epoxy resin 6 to seal the core in the other plastic shell 1, the contact between the core and the external environment is greatly isolated, so as to minimize the interference of the outside world. During the process of injecting epoxy resin 6, it is ensured that the epoxy resin 6 can fully penetrate into all parts of the core. By evacuating the inside of the other plastic shell 1 to remove the internal air, the epoxy resin 6 can naturally and evenly penetrate around the core.

[0023] The environmental conditions for the hot pressing process of the metal electrode 2 and the metallized film 3 are 7Mpa, 95°C, 700s to 720s; By adopting the above technical solution, the dielectric loss inside the capacitor is effectively reduced through hot pressing, which is a key step to improve the efficiency of the capacitor. The pressure inside the capacitor is evenly distributed, which can not only improve its working performance but also extend the service life of the capacitor. For high-voltage capacitors, hot pressing can also help to ensure the flatness of the pole piece and eliminate stress, and improve the insulation strength of the capacitor; improve the stability and efficiency of the capacitor in the electronic circuit, thereby improving the reliability of the entire electronic device. During the hot pressing process, capacitor manufacturing materials such as metal foil, polyethylene film, etc. will be affected by pressure and temperature, thereby improving their conductivity and mechanical strength, laying the foundation for the excellent performance of the capacitor.

[0024] The environmental conditions for thermal baking in the oven are 1.5h×85℃+1.5h×95℃+2h×115℃+6h×130℃; By adopting the above technical solution, the bulk baking shaping is mainly achieved through a specific heat treatment process. In the manufacturing process of the capacitor, after certain processing and assembly, the capacitor core needs to be heat-shaped. In this process, the capacitor core is placed in an oven and baked under certain temperature and time conditions to ensure that the inside and outside of the capacitor core shrink evenly and achieve the purpose of shaping; During the baking process, heat is transferred to the capacitor core through the oven, causing its temperature to rise. As the temperature rises, the material inside the capacitor core begins to expand thermally. However, due to the limitations of the external environment, the degree of expansion on the surface and inside of the capacitor core is not the same. In order to achieve uniform contraction inside and outside, it is necessary to control the baking temperature and time so that the degree of thermal expansion on the surface and inside of the capacitor core gradually becomes consistent. In addition, the stress release and volatilization of impurities inside the material during the baking process help improve the performance and stability of the capacitor.

[0025] The material of the metallized film 3 is polyimide PI and polyetheretherketone PEEK, the thickness of the metallized film 3 is controlled between 1 μm and 10 μm, and the material of the metal electrode 2 is aluminum or nickel-chromium alloy; By adopting the above technical solution, since both polyimide PI and polyetheretherketone PEEK have excellent high temperature resistance, they can work for a long time in an environment above 150°C, and in some cases, the temperature resistance of PEEK can reach 260°C. These two materials have excellent chemical stability and can resist corrosion from a variety of chemical substances, ensuring high-efficiency operation and improving the application ability of capacitors in harsh environments. At the same time, they can withstand greater mechanical stress and impact, ensuring durability and stability in electrical use. At the same time, the thickness of the metallized film 3 is controlled between 1 μm and 10 μm to optimize the capacitance and ESR (equivalent series resistance) characteristics of the capacitor. A thinner film thickness (such as 1 μm) can provide a higher capacitance value, while a thicker film (such as 10 μm) can improve the withstand voltage performance; The metallized film 3 structure can effectively filter out high-frequency noise and improve the stability of the power supply, especially in power supply filtering and high-frequency circuits. Aluminum and nickel-chromium alloy as electrode materials can provide good conductivity and low inductance.

[0026] The finished capacitors are tested for performance at high temperatures to detect their capacitance, leakage current and withstand voltage at temperatures of 125°C and above; By adopting the above technical solution, the high temperature resistant DC filter capacitor is inspected before leaving the factory. Only when the capacitor passes the inspection can it be determined to be a qualified product. This step is the key to ensuring the quality of the capacitor.

[0027] Embodiment 2: See also Figures 2 to 5 , the embodiment of the present application provides a capacitor, which is prepared according to a manufacturing method of a high temperature resistant filter capacitor; the square plastic shell 1 is arranged in a rectangular hollow shell, and a mounting cavity is arranged in the square plastic shell 1, and the wound metal electrode 2 and the metallized film 3 are arranged in the placement cavity of the square plastic shell 1, and the positive electrode sheet 21 and the negative electrode sheet 22 are respectively connected with a first lead pin 211 and a second lead pin 221, and the lead wire 4 is welded to the gold sprayed surface on the square plastic shell 1, and the first lead pin 211 and the second lead pin 221 are both connected to the lead wire 4; The protection assembly includes: a protection shell 7, a plurality of protection sleeves 8 and a plurality of fastening hoses 9. The protection shell 7 is sleeved on one end of the square plastic shell 1 connected to the lead 4. Both ends of the plurality of protection sleeves 8 are coaxially arranged with the plurality of fastening hoses 9. An installation cavity is arranged in the protection shell 7. One end of the plurality of protection sleeves 8 is arranged in the installation cavity. The plurality of fastening hoses 9 in the installation cavity are fixedly connected to the protection shell 7. The protection sleeve 8 is slidably connected to the installation cavity. A worm gear 12 is coaxially arranged on the fastening hose 9 outside the protective sleeve 8 arranged in the installation cavity, a worm 11 is arranged in the installation cavity, the worm 11 is rotatably connected with the installation cavity, the worm 11 is meshed with a plurality of worm gears 12 for transmission, a knob 10 is arranged on the outer wall of the square plastic shell 1, and the knob 10 is coaxially fixedly connected with the worm 11; The effect of such arrangement is that, by clamping the protective shell 7 on the end where the square plastic shell 1 is connected with the lead 4, after fixed installation, after connecting the lead 4 with the circuit, pull the fastening hose 9 on the protective sleeve 8 to cover the connection between the lead 4 and the circuit, heat the fastening hose 9 there and rotate it, and wait for natural cooling to stabilize; by rotating the knob 10, the worm 11 drives a group of worm wheels 12 to rotate synchronously, so that the fastening hose 9 located in the installation cavity of the protective shell 7 rotates and contracts to fix the end of the protective sleeve 8 located in the installation cavity. When rotating, the side wall is wrinkled and tightly attached to the end of the protective sleeve 8, fixing the end of the protective sleeve 8 in the installation cavity, so as to prevent the connection of the lead 4 from being affected by high temperature and moisture, thereby ensuring the normal service life of the capacitor.

[0028] From the above, we can see that the working principle of this application is as follows: The inner and outer electrodes of the capacitor are made of high-temperature resistant metal materials (such as aluminum, nickel-chromium alloy, etc.) to ensure good conductivity in high-temperature environments. The dielectric loss inside the capacitor is effectively reduced through hot pressing, which is a key step to improve the efficiency of the capacitor. The pressure inside the capacitor is evenly distributed, which can not only improve its working performance, but also extend the service life of the capacitor. For high-voltage capacitors, hot pressing also helps to ensure the flatness of the pole piece and eliminate stress, improve the insulation strength of the capacitor, improve the stability and efficiency of the capacitor in the electronic circuit, and thus improve the reliability of the entire electronic device; Prevent electrochemical reactions under extreme conditions; Based on the thermal effect and the physical properties of the material, during the baking process, the heat is transferred to the capacitor core through the oven, causing its temperature to rise. As the temperature rises, the material inside the capacitor core begins to expand thermally. Due to the limitations of the external environment, the expansion degree of the surface and the inside of the capacitor core is not the same. In order to achieve the effect of uniform contraction inside and outside, the baking temperature and time are controlled to make the thermal expansion degree of the surface and the inside of the capacitor core gradually tend to be consistent; This high-temperature resistant filter capacitor has been designed to meet the challenges in high-temperature environments by optimizing materials and structural design. It has efficient energy storage and stable electrical performance, ensuring that the connection between the two will not fail at high temperatures. The encapsulation layer not only protects the internal structure, but also ensures good sealing and oxidation resistance to prevent external factors from affecting the performance of the capacitor. The contact area of ​​the capacitor can be increased through the gold spraying process, and the reliability and stability of the connection can be improved. The spraying of metal or metal alloy can enhance the conductivity of the capacitor, thereby improving its storage capacity and discharge capacity. In addition, the gold spraying layer can also serve as a protective layer to prevent the capacitor from being damaged by the external environment, thereby extending the service life of the capacitor. By using epoxy resin 6 to potting the core in the other plastic shell 1, the contact between the core and the external environment is greatly isolated, so as to minimize the interference of the outside world; during the injection of epoxy resin 6, it is ensured that the epoxy resin 6 can fully penetrate into all parts of the core, and by vacuuming the other plastic shell 1 to remove the internal air, the epoxy resin 6 can be naturally and evenly penetrated around the core; By clamping the protective shell 7 on the end where the square plastic shell 1 is connected to the lead 4 and fixing it, after connecting the lead 4 to the circuit, pull the fastening hose 9 on the protective sleeve 8 to cover the connection between the lead 4 and the circuit, heat the fastening hose 9 at that location and rotate it, and wait for it to cool naturally and become stable; by rotating the knob 10, the worm 11 drives a group of worm wheels 12 to rotate synchronously, thereby causing the fastening hose 9 located in the installation cavity of the protective shell 7 to rotate and contract to fix one end of the protective sleeve 8 located in the installation cavity.

[0029] The above is only a preferred specific implementation of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved conception within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for manufacturing a high temperature resistant filter capacitor, characterized in that: The steps include: S10, providing a square plastic shell (1), a group of metal electrodes (2) and a metallized film (3), wherein the metallized film (3) is sandwiched between the group of metal electrodes (2), the group of metal electrodes (2) is divided into a positive electrode sheet (21) and a negative electrode sheet (22), the positive electrode sheet (21) and the negative electrode sheet (22) are respectively connected to a first lead pin (211) and a second lead pin (221), and the group of metal electrodes (2) and the metallized film (3) are wound into a core; S20, subjecting the wound set of the metal electrode (2) and the metallized film (3) to a hot pressing process, wherein the environmental conditions for the hot pressing process of the metal electrode (2) and the metallized film (3) are 7 MPa, 95° C., and 700 s to 720 s; S30, spraying metal or metal alloy onto the surface of the square plastic shell (1) and a group of metal electrodes (2) by means of a gold spraying process; S40, providing an oven, placing the metal electrode (2) and the metallized film (3) in the oven for thermal baking, wherein the environmental conditions for thermal baking in the oven are 1.5h×85°C+1.5h×95°C+2h×115°C+6h×130°C; S50, placing the metal electrode (2) and the metallized film (3) into the square plastic shell (1), and then placing the square plastic shell (1) in the center of the fixture of the energizing machine, ensuring that the capacitor is correctly placed, and then performing voltage energization and current energization on it; S60, providing a lead wire (4), welding the lead wire (4) to the gold-sprayed surface on the square plastic shell (1), and connecting the first lead pin (211) and the second lead pin (221) to the lead wire (4); S70, providing a potting material (5) and an epoxy resin (6), evacuating the square plastic shell (1) to remove the internal air, and filling the core and the inner wall of the square plastic shell (1) with the potting material (5); potting the square plastic shell (1) and the core with the epoxy resin (6) to form a finished capacitor, and a protective component is provided on the square plastic shell (1).

2. The method for manufacturing a high temperature resistant filter capacitor according to claim 1, characterized in that: The material of the metallized film (3) is polyimide (PI) and polyetheretherketone (PEEK).

3. The method for manufacturing a high temperature resistant filter capacitor according to claim 2, characterized in that: The thickness of the metallized film (3) is controlled between 1 μm and 10 μm.

4. The method for manufacturing a high temperature resistant filter capacitor according to claim 1, characterized in that: The material of the metal electrode (2) is aluminum or nickel-chromium alloy.

5. The method for manufacturing a high temperature resistant filter capacitor according to claim 1, characterized in that: The finished capacitor is subjected to performance testing at high temperature to detect its capacitance, leakage current and withstand voltage performance at temperatures of 125° C. and above.

6. A capacitor, characterized in that: The protective assembly is prepared by the method according to claims 1 to 5, comprising: a protective shell (7), a plurality of protective sleeves (8) and a plurality of fastening hoses (9), wherein the protective shell (7) is sleeved on one end of the square plastic shell (1) connected to the lead wire (4), and the two ends of the plurality of protective sleeves (8) are respectively coaxially arranged with the plurality of fastening hoses (9), and an installation cavity is arranged in the protective shell (7), and one end of each of the plurality of protective sleeves (8) is arranged in the installation cavity; A worm gear (12) is coaxially arranged on a fastening hose (9) outside the protective sleeve (8) arranged in the installation cavity. A worm (11) is arranged in the installation cavity. The worm (11) is meshed with a plurality of worm gears (12) for transmission. A knob (10) is arranged on the outer wall of the square plastic shell (1). The knob (10) is coaxially fixedly connected to the worm (11).

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