CN204706463U - High voltage thin film capacitor - Google Patents

Abstract

The utility model discloses a high-voltage film capacitor, which comprises: a casing, in which at least two cores encapsulated by epoxy resin and electrically connected in parallel are arranged, and each core is made of a double-sided electrode as an electrode. Metallized aluminum material, double-sided metallized aluminum material as electrode 2, and polypropylene film as a medium layer between electrode 1 and electrode 2 are rolled into a double-electrode columnar body; the first lead-out electrode is arranged on the shell, The lower end of the first lead-out electrode is packaged and fixed in epoxy resin and electrically connected to the electrodes of each core through a wire, and the upper end extends out of the shell; the second lead-out electrode is arranged on the shell, and the lower end of the second lead-out electrode The package is fixed in the epoxy resin and is electrically connected with the second electrode of each core through a wire, and the upper end protrudes out of the shell. The film capacitor has high working voltage, good impact current resistance, small size and self-healing property.

Description

High Voltage Film Capacitors

technical field

The utility model relates to the field of capacitors, in particular to a high-voltage film capacitor.

Background technique

At present, most of the capacitors in the 1000V AC circuit use two aluminum electrolytic capacitors with a rated voltage of 500V in series. A voltage balancing system needs to be made between the two capacitors to balance the voltage between the two capacitors to avoid a single capacitor. If the voltage is too high, it will be broken down and fail, so that the whole system will become complicated, and the reliability and safety of the aluminum electrolytic capacitor will also be reduced. If film capacitors are used, only one AC film capacitor with a working voltage of 1000V is required, and no voltage balance is required, and the whole system will become simpler. Compared with aluminum electrolytic capacitors, film capacitors have higher single operating voltage, higher reliability, long service life, safety and environmental protection, and have been widely used in medium and high voltage fields.

An existing film capacitor uses a single-sided metallized film as the dielectric layer. A single capacitor core with a certain capacity is formed through a winding process, and a capacitor electrode is formed through a gold spraying process. Reject, and then form a complete finished product through welding and assembly. This single-sided metallized film capacitor has the characteristics of high withstand voltage, small loss tangent, high insulation resistance, small size, good self-healing property, and long service life. The resistance is large, and the equivalent series resistance of the capacitor is also large, resulting in high active power of the capacitor and low impact current resistance.

Another existing film capacitor uses metal foil as the electrode and plastic film as the dielectric layer. A single capacitor core with a certain capacity is formed by winding process, and the capacitor electrode is formed by gold spraying process, and then a capacitor electrode is formed by welding and assembling. complete finished product. This kind of film capacitor using metal foil has high withstand voltage, small loss tangent, high insulation resistance, high dv/dt value, and good impact current resistance. The disadvantage is that the capacitor has no self-healing property, and the reliability of the capacitor is relatively low. low, the volume of the capacitor is larger.

Utility model content

Based on the above-mentioned problems in the prior art, the utility model provides a high-voltage film capacitor, which has high working voltage, good impact current resistance, small volume and self-healing property.

In order to solve the above technical problems, the utility model provides a high-voltage film capacitor, including:

The shell, which is provided with at least two cores encapsulated by epoxy resin and electrically connected in parallel, each core is made of double-sided metallized aluminum material as electrode 1 and double-sided metallized aluminum material as electrode 2 A double-electrode columnar body co-rolled with a polypropylene film as a dielectric layer between the first electrode and the second electrode;

The first lead-out electrode is arranged on the shell, the lower end of the first lead-out electrode is packaged and fixed in the epoxy resin and electrically connected with the electrodes of each core through a wire, and the upper end extends out of the shell;

The second lead-out electrode is arranged on the shell, the lower end of the second lead-out electrode is packaged and fixed in the epoxy resin and is electrically connected with the second electrode of each core through a wire, and the upper end of the second lead-out electrode protrudes out of the shell.

The beneficial effects of the utility model are: the core of the capacitor is made of double-sided metallized aluminum as two electrodes and a polypropylene film as a dielectric layer. The polypropylene film is non-polar and can withstand 200V AC per micron thickness. voltage, the insulation resistance can reach 10MΩ, and the loss tangent value is not greater than 2×10 ^-4 . Because the polypropylene film has the above excellent characteristics, the electrical performance of the film capacitor also reaches its working voltage of 1000V, the loss tangent value reaches 10 ^-4 level, the insulation resistance value reaches more than 100MΩ, the dv/dt value is high, and the impact current is high. In addition, the core uses double-sided metallized aluminum as the electrode. This electrode lead-out method not only has the self-healing characteristics of single-sided metallized metal as the electrode, but also has the advantages of metal foil as the electrode. It has the characteristics of high impact current resistance, but at the same time overcomes the shortcomings of single-sided metallization's weak impact current resistance and the lack of self-healing and large volume of metal foil.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention , for those skilled in the art, other drawings can also be obtained based on these drawings without creative work.

Fig. 1 is the schematic diagram of the longitudinal section structure of the high-voltage film capacitor provided by the embodiment of the utility model;

The components corresponding to the symbols in the figure are: 1. Core, 2. Core group, 3. First lead-out electrode, 4. Epoxy resin, 5. Shell, 6. Insulation layer, 7. Second lead-out electrode.

Detailed ways

The technical solutions in the embodiments of the utility model are clearly and completely described below, obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present utility model.

The capacitor of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the embodiment of the utility model provides a high-voltage film capacitor, which is a film capacitor with high working voltage, good impact current resistance, small volume and self-healing property. The capacitor includes:

The shell, which is provided with at least two cores encapsulated by epoxy resin and electrically connected in parallel, each core is made of double-sided metallized aluminum material as electrode 1 and double-sided metallized aluminum material as electrode 2 A double-electrode columnar body rolled together with a polypropylene film as a dielectric layer between the first electrode and the second electrode;

The first lead-out electrode is arranged on the shell, the lower end of the first lead-out electrode is packaged and fixed in the epoxy resin and is electrically connected with the electrodes of each core through a wire, and the upper end extends out of the shell;

The second lead-out electrode is arranged on the casing, the lower end of the second lead-out electrode is packaged and fixed in the epoxy resin and is electrically connected with the second electrode of each core through a wire, and the upper end of the second lead-out electrode extends out of the casing.

In the above-mentioned film capacitor, the shell is a metal shell, and the first lead-out electrode and the second lead-out electrode are insulated from the metal shell; it also includes: an insulating layer, which is arranged around the periphery of each core, and is packaged with each core in epoxy In the resin, between each core and the metal shell. Preferably, the metal casing is an aluminum casing or an iron casing. The reliability of this metal case film capacitor is improved by providing an insulating layer. The shell can also be made of plastic.

In the above-mentioned film capacitor, the first lead-out electrode and the second lead-out electrode both use any one of metal column wires, metal soft electrodes or metal soldering sheet electrodes. Preferably, both the first extraction electrode and the second extraction electrode use columnar wires. Both the first lead-out electrode and the second lead-out electrode can be arranged on the same side of the shell (leading in the same direction) or on both sides of the upper and lower end surfaces of the shell (leading out in the axial direction).

As shown in Figure 1, when the capacitor is prepared, the double-sided metallized aluminum is used as the electrode material, and the polypropylene film is used as the dielectric layer. After winding process, the core required for the capacitor is formed, and then the two cores are assembled and welded in parallel. For the core group with double core structure, the core group is insulated and wrapped to form an insulating layer and put into the aluminum shell and sealed with epoxy resin. After the epoxy resin is cured, the capacitance, withstand voltage, and loss tangent Value, insulation resistance parameter test. Preferably, the shell can also be made of iron or plastic. If the shell is made of plastic, the core group can not be insulated and wrapped. , solder lug type.

Because the capacitor uses polypropylene film as its dielectric layer, the polypropylene film is non-polar, can withstand 200V AC voltage per micron thickness, its insulation resistance can reach 10MΩ, and the loss tangent value is not more than 2×10 ^-4 . Because the polypropylene film has the above excellent characteristics, the electrical performance of the film capacitor of the utility model invention also reaches 1000V, the loss tangent value will reach 10 ^-4 level, and the insulation resistance value will reach more than 100MΩ, dv/dt High value, good impact current resistance, small size. In addition, the two electrodes of the capacitor use double-sided metallized aluminum as electrodes. This electrode extraction method not only has the self-healing characteristics of single-sided metallized metal as electrodes, but also has the advantages of metal foil as electrodes. It has the characteristics of high impact current resistance, but at the same time overcomes the disadvantages of single-sided metallization's weak resistance to impact current and the shortcomings of metal foil without self-healing property and large volume. The sealing material of the capacitor is to use epoxy resin dry packaging, and epoxy resin has the advantages of good sealing, low price, and environmental protection. The internal structure of the capacitor adopts double-core parallel connection. This structure is designed to reduce the internal resistance of the capacitor, reduce the heat generated by the capacitor during use, and increase the service life of the capacitor. In particular, it is safer and has a longer service life when used in medium and high voltage AC circuits or pulse circuits.

The above is only a preferred embodiment of the utility model, but the scope of protection of the utility model is not limited thereto, and any person familiar with the technical field can easily think of All changes or replacements should fall within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims (7)

1. A high-voltage film capacitor, characterized in that the capacitor comprises: The shell, which is provided with at least two cores encapsulated by epoxy resin and electrically connected in parallel, each core is made of double-sided metallized aluminum material as electrode 1 and double-sided metallized aluminum material as electrode 2 A double-electrode columnar body co-rolled with a polypropylene film as a dielectric layer between the first electrode and the second electrode; The first lead-out electrode is arranged on the shell, the lower end of the first lead-out electrode is packaged and fixed in the epoxy resin and electrically connected with the electrodes of each core through a wire, and the upper end extends out of the shell; The second lead-out electrode is arranged on the shell, the lower end of the second lead-out electrode is packaged and fixed in the epoxy resin and is electrically connected with the second electrode of each core through a wire, and the upper end of the second lead-out electrode protrudes out of the shell. 2. The high-voltage film capacitor according to claim 1, wherein the shell is a metal shell, and the first lead-out electrode and the second lead-out electrode are insulated from the metal shell; It also includes: an insulating layer arranged around the outer periphery of each core, packaged together with each core in the epoxy resin, and interposed between each core and the metal shell. 3. The high-voltage film capacitor according to claim 2, wherein the metal casing is an aluminum casing or an iron casing. 4. The high-voltage film capacitor according to claim 1, characterized in that, the casing is made of plastic. 5. The high-voltage film capacitor according to any one of claims 1 to 4, characterized in that, the first lead-out electrode and the second lead-out electrode are metal column wires, metal flexible electrodes or metal soldering electrodes. any item. 6 . The high-voltage film capacitor according to claim 5 , wherein the first lead-out electrode and the second lead-out electrode both use metal pillar wires, metal soft wires or metal soldering pieces. 7. The high-voltage film capacitor according to any one of claims 1 to 4, wherein the first lead-out electrode and the second lead-out electrode are both arranged on the same side of the casing or on both sides of the upper and lower end surfaces of the casing .