Metallized film without partial discharge

Abstract

The utility model discloses a metallized film without partial discharge, relates to the technical field of metallized films, and aims to solve the problems that air gap residues are inevitably left between two layers of metallized films, a dielectric layer and an air gap layer form partial pressure when the residual air gap has potential difference between metal layers, and when an electric field in the air gap is higher than a certain degree, the partial discharge is not generated. The ultra-high sheet resistance metal film comprises a plastic film layer and a first metal layer, and further comprises an ultra-high sheet resistance metal layer, and the thickness of one end, flush with the plastic film layer, of the first metal layer is larger than that of the other end of the first metal layer; according to the utility model, through the arrangement of the ultrahigh sheet resistance metal layers, the metal layers are arranged on the two surfaces of the plastic film layer, so that when a plurality of metallized film structures are wound to form a capacitor element, an air gap between two layers of metallized films is changed from a position between the metal layers and a medium to a position between two equipotential metal layers of the two films, and the air gap does not divide voltage any more; and the partial discharge phenomenon disappears.

Description

Technical Field

[0001] The utility model relates to the technical field of metallized films, in particular to a metallized film without partial discharge. Background Art

[0002] Metal layer + dielectric are collectively referred to as metallized film. Although the final metallized film finished capacitor process has gone through multiple steps, there is inevitably residual air gap between the two layers of metallized film (between the dielectric of one film and the metal layer of another film). This residual air gap is not only related to the process, but also to the existing equipment limit and the surface microscopic state of the metallized film material.

[0003] When there is a potential difference between the metal layers in the residual air gap, a voltage divider is formed between the dielectric layer and the air gap layer. When the electric field in the air gap is higher than a certain level, local discharge occurs, which breaks down the air gap. As a result, the dielectric near the discharge position will be slowly destroyed, and complete breakdown will occur under long-term continuous destruction. Multiple complete breakdowns will eventually lead to capacitor failure breakdown when self-healing fails. Utility Model Content

[0004] In order to solve the above technical problems, a metallized film without local discharge is provided, which solves the problem that there are inevitably residual air gaps between the two layers of metallized films in the prior art. When there is a potential difference between the metal layers in the residual air gap, the dielectric layer and the air gap layer form a voltage divider. When the electric field in the air gap is higher than a certain level, local discharge that breaks through the air gap will occur.

[0005] To achieve the above purpose, the technical solution adopted by the utility model is: a metallized film without partial discharge, comprising a plastic film layer and a first metal layer arranged on one side of the plastic film layer, one end of the first metal layer is flush with one end of the plastic film layer, and also includes an ultra-high square resistance metal layer arranged on the bottom surface of the plastic film layer, a second metal layer is arranged on the side of the plastic film layer, the second metal layer covers one side of the first metal layer and the ultra-high square resistance metal layer, and the thickness of the end of the first metal layer flush with the plastic film layer is greater than the thickness of the other end.

[0006] Preferably, a notch is symmetrically formed at one end of the plastic film layer, a plastic bubble film is built into the notch, and the plastic bubble film is in contact with the second metal layer.

[0007] Preferably, the first metal layer, the ultra-high square resistance metal layer and the second metal layer are all evaporated metal layers.

[0008] Compared with the prior art, the advantages of the utility model are:

[0009] (1) By setting an ultra-high square resistance metal layer, the structure of the single-sided metal layer of the plastic film layer in the prior art is replaced, so that the plastic film layer has metal layers on both sides. Then, when multiple metallized film structures are wound and set to form a capacitor element, the ultra-high square resistance metal layer is correspondingly bonded to the first metal layer of another film close to it. In this way, the air gap between the two metallized films will change from between the metal layer and the dielectric to between the two films with equal potential metal layers. The air gap no longer divides the pressure, the local discharge phenomenon disappears, and the dielectric no longer suffers from the slow destruction of local discharge. The capacitor failure rate can be greatly reduced, and the capacity decay slows down in actual use, which has a positive significance for improving the life of the metallized film capacitor.

[0010] (2) By increasing the thickness of one end of the first metal layer and providing the second metal layer, the second metal layer can effectively cover the plastic film layer, the first metal layer and the side of the ultra-high square resistance metal layer. When gold is sprayed on the side, the surface of the second metal layer can be completely covered by the gold spray layer. In addition, the increase in the thickness of one end of the first metal layer can relatively expand the surface area of ​​the second metal layer. Similarly, the coverage range of the gold spray layer on the surface of the second metal layer can be further promoted, so that the contact area between the gold spray layer and the side of the entire metal layer is effectively increased, thereby reducing the contact resistance of the metallized film capacitor, which is beneficial to improving the service stability and life of the capacitor element.

[0011] (3) By setting the plastic bubble film, when the plastic film layer is rolled up and hot-pressed, the plastic bubble film can be expanded toward the side away from the plastic film layer under pressure, thereby forming a certain protrusion on the surface of the second metal layer. The protrusion makes the surface of the second metal layer uneven and the roughness increases, which is beneficial to improve the adhesion of the gold-sprayed layer on the surface of the second metal layer during the subsequent gold-spraying. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0013] The numbers in the figure are:

[0014] 1. Plastic film layer; 2. First metal layer; 3. Ultra-high square resistance metal layer; 4. Plastic bubble film; 5. Second metal layer. DETAILED DESCRIPTION

[0015] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0016] Reference Figure 1As shown, a metallized film without partial discharge comprises a plastic film layer 1 and a first metal layer 2 arranged on one side of the plastic film layer 1, wherein one end of the first metal layer 2 is flush with one end of the plastic film layer 1;

[0017] The plastic film layer 1 and the first metal layer 2 are arranged to form a main structure of the metallized film structure, which facilitates winding and arranging of multiple metallized film structures to form capacitor elements.

[0018] Further, refer to Figure 1 As shown, it is worth noting that it also includes an ultra-high square resistance metal layer 3 arranged on the bottom surface of the plastic film layer 1;

[0019] By setting the ultra-high square resistance metal layer 3, the structure of the single-sided metal layer of the plastic film layer 1 in the prior art is replaced, so that the plastic film layer 1 has metal layers on both sides, and then when multiple metallized film structures are wound and set to form a capacitor element, the ultra-high square resistance metal layer 3 is correspondingly bonded to the first metal layer 2 of another film close to it, so that the air gap between the two metallized films will change from between the metal layer and the medium to between the two films with equipotential metal layers, the air gap will no longer divide the pressure, the local discharge phenomenon will disappear, the medium will no longer bear the slow destruction of local discharge, the capacitor failure rate can be greatly reduced, and the capacity decay will slow down in actual use, which has positive significance for improving the life of the metallized film capacitor.

[0020] Although the above-mentioned embodiment utilizes the setting of the ultra-high square resistance metal layer 3 to solve the problem of local discharge of the metallized film capacitor, when the side of the structure is sprayed with gold, the contact between the first metal layer 2 and the ultra-high square resistance metal layer 3 and the gold sprayed layer is often only the relative side area. The actual coverage area of ​​the first metal layer 2 and the ultra-high square resistance metal layer 3 by the gold sprayed layer is small. The small contact area easily makes the metallized film capacitor have a large contact resistance, affecting the stability and life of the capacitor.

[0021] For this purpose, refer to Figure 1 As shown, it is worth noting that the thickness of the end of the first metal layer 2 flush with the plastic film layer 1 is greater than the thickness of the other end thereof, and the side of the plastic film layer 1 is provided with a second metal layer 5, and the second metal layer 5 covers one side of the first metal layer 2 and the ultra-high square resistance metal layer 3, and the first metal layer 2, the ultra-high square resistance metal layer 3 and the second metal layer 5 are all evaporated metal layers;

[0022] By increasing the thickness of one end of the first metal layer 2 and providing the second metal layer 5, the second metal layer 5 can effectively cover the plastic film layer 1, the first metal layer 2 and the side of the ultra-high square resistance metal layer 3, and then when gold is sprayed on the side, the surface of the second metal layer 5 can be completely covered by the gold spray layer, and the increase in the thickness of one end of the first metal layer 2 can relatively expand the surface area of ​​the second metal layer 5. Similarly, the coverage range of the gold spray layer on the surface of the second metal layer 5 can be further promoted, so that the contact area between the gold spray layer and the side of the entire metal layer is effectively improved, thereby reducing the contact resistance of the metallized film capacitor, which is beneficial to improving the service stability and life of the capacitor element.

[0023] Further, refer to Figure 1 As shown, it is worth noting that a notch is symmetrically opened at one end of the plastic film layer 1, a plastic bubble film 4 is built into the notch, and the plastic bubble film 4 is in contact with the second metal layer 5;

[0024] By setting the plastic bubble film 4, when the plastic film layer 1 is hot-pressed after being wound as a whole, the plastic bubble film 4 can be expanded to the side away from the plastic film layer 1 under pressure, thereby forming a certain protrusion on the surface of the second metal layer 5. The protrusion makes the surface of the second metal layer 5 uneven and the roughness increased, which is beneficial to improve the adhesion of the gold-sprayed layer on the surface of the second metal layer 5 during the later gold-spraying.

[0025] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and the specification only describe the principles of the utility model. The utility model may be subject to various changes and improvements without departing from the spirit and scope of the utility model. These changes and improvements fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A metallized film without partial discharge, comprising a plastic film layer (1) and a first metal layer (2) arranged on one side of the plastic film layer (1), one end of the first metal layer (2) being flush with one end of the plastic film layer (1), characterized in that: It also comprises an ultra-high square resistance metal layer (3) arranged on the bottom surface of the plastic film layer (1), a second metal layer (5) is arranged on the side of the plastic film layer (1), the second metal layer (5) covers the first metal layer (2) and one side of the ultra-high square resistance metal layer (3), and the thickness of the first metal layer (2) at one end flush with the plastic film layer (1) is greater than the thickness at the other end.

2. A partial discharge-free metallized film according to claim 1, characterized in that: A notch is symmetrically formed at one end of the plastic film layer (1), a plastic bubble film (4) is built into the notch, and the plastic bubble film (4) is in contact with the second metal layer (5).

3. A partial discharge-free metallized film according to claim 2, characterized in that: The first metal layer (2), the ultra-high square resistance metal layer (3) and the second metal layer (5) are all evaporated metal layers.

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