Thin film capacitor with excellent moisture resistance

Abstract

The utility model discloses a film capacitor with excellent moisture resistance, which comprises leads, a capacitor core, a shell and a potting material, the capacitor core is formed by winding a metallized film, the two leads are welded on the two sides of the capacitor core, and the surface of the capacitor core is coated with a layer of nano waterproof material to form a waterproof spray layer I; the capacitor core is arranged in a shell made of a plastic material and is packaged by a potting compound to form a metallized film capacitor; according to the utility model, the packaging of the metallized film capacitor is innovated, and the waterproof spray layers are sprayed outside the capacitor core and on the inner wall of the plastic shell, so that the moisture resistance of the product is improved, and the damage to the inner metallized film caused by water vapor invasion in the use process is reduced; the method has the advantages of low cost, easy operation, high efficiency and high reliability.

Description

Technical Field

[0001] The utility model relates to the technical field of thin film capacitor structures, and particularly relates to a thin film capacitor with excellent moisture resistance performance. Background Art

[0002] The metallized film capacitor is a main electronic component in electronic devices. The metallized film capacitor adopts a non-inductive winding structure of metallized film, has good self-healing performance, high insulation resistance, and stable capacitance. It is suitable for DC and pulsating circuits and is widely used in various electronic appliances, electrical equipment, and filtering, DC blocking, bypass, coupling, and noise reduction in the new energy field.

[0003] At present, the moisture resistance performance of metallized film capacitors, especially metallized films, is relatively poor. Because the metallized film is a zinc-aluminum metal evaporated on the film surface with a thickness of nanometers, it is very easy to oxidize. During use, the metal layer oxidizes, the loss of the capacitor increases, the thin film capacitor heats up, the heat causes the internal metal layer to oxidize more severely, the loss increases more, and finally a vicious cycle is caused, and even the product melts through and even safety problems such as combustion occur. Therefore, how to improve the moisture resistance performance of metallized film capacitors is to do a good job in moisture resistance protection for the metal layer of the metallized film.

[0004] The current main method is to coat a layer of antioxidant silicone oil with a nanometer-level thickness on the surface of the metal layer during the manufacturing process of the metallized film. However, due to the high-temperature treatment during the production process of the metallized film capacitor, the antioxidant silicone oil will volatilize, and finally the protection effect on the metal layer is not good. Especially as the use time goes by, the antioxidant ability of the silicone oil gradually decreases, and finally the product fails.

[0005] At present, the encapsulation of the metallized film capacitor is mainly a plastic shell on the outside, a core formed by winding the metallized film inside, and epoxy resin potting glue is filled in the middle. Specifically Figure 1 As shown, because the plastic shell and the potting material have a certain water absorption. For example, most plastic shells use PBT, and the water absorption rate of PBT is 0.1%. At the same time, because the epoxy resin potting material is filled with inorganic powder objects inside, its absorption rate is generally between 1% and 3%. During the long-term humid and hot use environment, water vapor will slowly penetrate into the inside to contact the core, and finally oxidize the metal layer of the metallized film. Content of the Utility Model

[0006] The purpose of the utility model is to provide a thin film capacitor with excellent moisture resistance performance.

[0007] The above technical purpose of the utility model is achieved through the following technical solutions:

[0008] A thin-film capacitor with excellent moisture resistance, comprising leads, a capacitor core, a housing and potting material. The capacitor core is formed by winding a metallized film. Two leads are welded on both sides of the capacitor core. A nano waterproof material is coated on the surface of the capacitor core to form a first waterproof spray layer. The capacitor core is placed into a housing made of plastic material and encapsulated with potting material to form a metallized film capacitor.

[0009] Further, a second waterproof spray layer is sprayed on the inner wall of the housing.

[0010] Preferably, the first waterproof spray layer and the second waterproof spray layer adopt nano silica sol waterproof materials.

[0011] Further, the potting material adopts epoxy resin.

[0012] In summary, the present utility model has the following beneficial effects: By innovating the encapsulation of the metallized film capacitor, waterproof spray layers are sprayed on the outside of the capacitor core and the inner wall of the plastic housing, improving the moisture resistance of the product, reducing the damage to the internal metallized film caused by water vapor intrusion during use, simply isolating water vapor, and having the advantages of low cost, easy operation, high efficiency and high reliability. Description of the Drawings

[0013] Figure 1 is a schematic diagram of the encapsulation structure of a prior art thin-film capacitor;

[0014] Figure 2 is a schematic diagram of the encapsulation structure of Embodiment 1;

[0015] Figure 3 is a schematic diagram of the encapsulation structure of Embodiment 2.

[0016] In the figure, 1, leads; 2, capacitor core; 3, housing; 4, potting material; 5, first waterproof spray layer; 6, second waterproof spray layer. Detailed Description of the Embodiments

[0017] The following further describes the present utility model in detail with reference to the drawings. The technical solutions in the embodiments of the present utility model are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0018] Embodiment 1: As Figure 2As shown in the figure, a film capacitor with excellent moisture resistance performance includes leads 1, a capacitor core 2, a housing 3, and potting compound 4. The capacitor core 2 is formed by winding a metallized film. Two leads 1 are welded to both sides of the capacitor core 2. A nano waterproof material is coated on the surface of the capacitor core 2. Preferably, the nano waterproof material uses nano silica sol waterproof material to form a first waterproof spray layer 5. The capacitor core 2 is placed into a housing 3 made of plastic material and encapsulated by the potting compound 4. Among them, the potting compound 4 uses epoxy resin to form a metallized film capacitor.

[0019] Production process: First, weld two leads to both sides of the capacitor core, spray the waterproof material on the surface of the capacitor core to form a first waterproof spray layer. Place the capacitor core into the housing and encapsulate and cure it with the potting compound. After curing, conduct electrical testing. The products that pass the electrical testing are qualified products.

[0020] Embodiment 2: As shown in Figure 3, on the basis of Embodiment 1, a second waterproof spray layer 6 is sprayed on the inner wall of the housing 3, and the second waterproof spray layer 6 and the first waterproof spray layer 5 use the same material.

[0021] Production process: First, weld two leads to both sides of the capacitor core, spray the waterproof material on the surface of the capacitor core to form a first waterproof spray layer, spray the waterproof material on the inner wall of the housing to form a second waterproof spray layer. Place the capacitor core into the housing and encapsulate and cure it with the potting compound. After curing, conduct electrical testing. The products that pass the electrical testing are qualified products.

[0022] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions according to needs, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A film capacitor with excellent moisture resistance, comprising a lead wire (1), a capacitor core (2), a shell (3) and a potting material (4), wherein the capacitor core (2) is formed by winding a metallized film, and two lead wires (1) are welded to two sides of the capacitor core (2), characterized in that: The surface of the capacitor core (2) is coated with a layer of nano waterproof material to form a waterproof spray layer (5); the capacitor core (2) is placed in a plastic shell (3) and encapsulated with a potting material (4) to form a metallized film capacitor.

2. A film capacitor with excellent moisture resistance according to claim 1, characterized in that: The inner wall of the outer shell (3) is sprayed with a second waterproof spray layer (6).

3. A film capacitor with excellent moisture resistance according to claim 2, characterized in that: The waterproof spray layer 1 (5) and the waterproof spray layer 2 (6) are made of nano-silica sol waterproof material.

4. A film capacitor with excellent moisture resistance according to claim 3, characterized in that: The potting material (4) is made of epoxy resin.

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