Safety film structure and film capacitor having the same

Abstract

The present application discloses a safety film structure and a film capacitor having the same, comprising: an insulating base film; a metal coating, the metal coating is arranged on the insulating base film, a blank area is formed between the metal coating and the first long side of the insulating base film, an insulating gap structure is arranged in the metal coating, the insulating gap structure comprises a plurality of insulating gap parts, the insulating gap parts comprise a first gap and a second gap both of which are T-shaped, the second gap is located on the side of the first gap close to the first long side, the vertical section in the first gap is connected to the horizontal section in the second gap, and the vertical section in the second gap extends to the blank area. The safety film structure provided by the present application and the film capacitor having the same can increase the total capacitance of the film capacitor and reduce the self-healing capacitance loss of the film capacitor under the condition of the same size of metallized film, achieve a balance between the total capacitance and the self-healing capacitance loss of the film capacitor, and improve the capacity performance of the film capacitor.

Description

Technical Field

[0001] The present invention generally relates to the technical field of capacitors, and in particular to a safety film structure and a film capacitor having the same. Background Art

[0002] Film capacitors are capacitors made by winding with insulating film as dielectric and metallized coating as electrode. An insulating gap structure is set on the metallized coating, and the metallized coating with insulating gap structure and insulating film form a safety film. Please refer to the attached Figure 1-2 The insulating gap structure 1 in the existing safety film is mainly T-shaped or grid-shaped to divide the metallized film into a plurality of electrode units 2, wherein a fuse 3 is provided between two adjacent electrode units. The safety film having a T-shaped insulating gap structure is called a T-type safety film, and the safety film having a grid-shaped insulating gap structure is called a grid-type safety film.

[0003] Compared with the T-type safety film and the grid-type safety film, the electrode unit in the T-type safety film suffers relatively large capacitance loss due to short-circuit breakdown, that is, the self-healing capacitance loss of the T-type safety film is relatively large. Although the natural capacitance loss of the grid-type safety film is small, the original total capacitance is relatively low, making it difficult for existing film capacitors to strike a balance between the total capacitance and the self-healing capacitance loss. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a safety film structure and a thin film capacitor having the same.

[0005] In a first aspect, the present application provides a safety membrane structure, comprising:

[0006] An insulating base film having a first long side;

[0007] A metal plating layer, wherein the metal plating layer is arranged on an insulating base film, a blank area is formed between the metal plating layer and the first long side, an insulating gap structure is arranged in the metal plating layer, the insulating gap structure includes a plurality of insulating gap portions arranged at intervals along the length direction of the insulating base film, the insulating gap portions include a first gap and a second gap both of which are T-shaped, the second gap is located on a side of the first gap close to the first long side, the vertical segment in the first gap is connected to the horizontal segment in the second gap, and the vertical segment in the second gap extends to the blank area.

[0008] Furthermore, the first gap is located in the middle of the metal plating layer, the distance from the horizontal section in the first gap to the blank area is D1, the distance from the horizontal section in the second gap to the blank area is D2, and 0.4≤D2 / D1≤0.5.

[0009] Furthermore, the metal plating layer is divided into a plurality of electrode units by an insulating gap structure, a conductive first fuse portion is arranged in the vertical section in the second gap, and the first fuse portion is conductively connected to the electrode units located on both sides thereof.

[0010] Furthermore, the metal plating layer is divided into a plurality of electrode units by the insulating gap structure, and the two electrode units between any two adjacent insulating gap portions are staggered along the length direction of the insulating base film.

[0011] Furthermore, in the two electrode units that are staggered, the distance between the same sides of the two electrode units is 0.6-1.2 mm.

[0012] Furthermore, the spacing between the transverse sections in any two adjacent first gaps is 0.1-0.3 mm, and the spacing between the transverse sections in any two adjacent second gaps is 0.1-0.3 mm.

[0013] Furthermore, the height of the horizontal segment in the first gap is 0.1-0.3 mm, the length of the vertical segment in the first gap is 0.1-0.3 mm, the height of the horizontal segment in the second gap is 0.1-0.3 mm, and the length of the vertical segment in the second gap is 0.1-0.3 mm.

[0014] Furthermore, the transverse segments in any two adjacent first gaps are arranged flush along the length direction of the insulating base film; in the insulating gap portion, the transverse segment in the first gap and the transverse segment in the second gap are aligned in the height direction of the insulating base film.

[0015] In a second aspect, the present application also provides a thin film capacitor including a safety film structure.

[0016] The safety film structure and the thin film capacitor having the same provided by the present application are characterized by arranging a plurality of insulating gap portions spaced apart along the length direction of the insulating base film in the metal plating layer, wherein the insulating gap portions include a T-shaped first gap and a T-shaped second gap arranged up and down, wherein the vertical section in the first gap is connected to the horizontal section in the second gap, and the vertical section in the second gap extends to the blank area. The total capacitance of the thin film capacitor can be increased and the self-healing capacitance loss of the thin film capacitor can be reduced under the condition of the same size of the metallized film, thereby achieving a balance between the total capacitance and the self-healing capacitance loss of the thin film capacitor and improving the capacity performance of the thin film capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0018] Figure 1 It is a structural schematic diagram of an existing T-type safety membrane;

[0019] Figure 2 It is a structural schematic diagram of an existing grid-type safety film;

[0020] Figure 3 A schematic diagram of the structure of the safety membrane provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the inventions. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0022] Please refer to the attached Figure 3 , the embodiment of the present application provides a safety film structure for a thin film capacitor. The safety film structure includes an insulating base film 100 and a metal coating 200. The insulating base film 100 is usually rectangular, but not limited to a rectangle. The insulating base film 100 has a first long side 101, and the first long side 101 is a side of the insulating base film 100 along the length direction. The insulating base film 100 has a first side and a second side opposite to each other along the thickness direction, and the metal coating 200 is arranged on the first side of the insulating base film 100. A blank area 102 is formed between the metal coating 200 and the first long side 101. The blank area 102 refers to an area where the metal coating 200 is not provided, which is used to constitute an insulating area. The metal coating 200 can be formed on the first side of the insulating base film 100 by, but not limited to, processes such as evaporation. An insulating gap structure 300 is provided in the metal coating 200 to divide the metal coating 200 into a plurality of electrode units, and the insulating gap structure 300 is a gap where the metal coating is not provided. The insulating gap structure 300 includes a plurality of insulating gap portions 310, and the plurality of insulating gap portions 310 are arranged at intervals along the length direction of the insulating base film 100. The insulating gap portions 310 include a first gap 311 and a second gap 312, both of which are T-shaped. The first gap 311 and the second gap 312 are arranged in sequence along the height direction of the insulating base film 100, and the second gap 312 is located on the side of the first gap 311 close to the first long side 101. The first gap 311 and the second gap 312 both include a horizontal section 316 and a vertical section 317, and the vertical section 317 is located on the side of the horizontal section 316 close to the first long side 101. The vertical section 317 in the first gap 311 is connected to the horizontal section 316 in the second gap 312, and the vertical section 317 in the second gap 312 extends to the blank area 102.

[0023] The height of the insulating gap structure 300 is greater than half the height of the metal coating 200. The plurality of electrode units include a first electrode unit 110, a plurality of second electrode units 120, and a plurality of third electrode units 130. The first electrode unit 110 is located on the side of the insulating gap structure 300 away from the blank area 102, the second electrode unit 120 is composed of a portion of the metal coating 200 located between two adjacent first gaps 311, and the third electrode unit 130 is composed of a portion of the metal coating 200 located between two adjacent second gaps 312. Since the plurality of insulating gap portions 310 in the insulating gap structure 300 are arranged at intervals along the length direction of the insulating base film 100, a portion of the metal coating 200 is provided between the transverse sections 316 in any two adjacent first gaps 311, and the portion of the metal film is the second fuse portion 314, and a portion of the metal coating 200 is provided between the transverse sections 316 in any two adjacent second gaps 312, and the portion of the metal film is the third fuse portion 315. The length of the second fuse part 314 is smaller than that of the first electrode unit 110 and the second electrode unit 120, and the length of the third fuse part 315 is smaller than that of the second electrode unit 120 and the third electrode unit 130. The second fuse part 314 and the third fuse part 315 are both used as fuse structures to be blown by the large current generated after an adjacent electrode unit is short-circuited and broken down, so as to protect other adjacent electrode units.

[0024] Under the condition of the same size metal plating layer 200, the relative Figure 1 Compared with the conventional T-shaped safety membrane structure shown in the figure, the electrode unit in the safety membrane structure provided in this embodiment has a smaller area, so that the self-healing capacitance loss of the film capacitor is smaller, and the thickness of the electrode unit is smaller than that of the electrode unit in the embodiment. Figure 2 The existing grid-type safety membrane structure shown in the figure has an insulating gap structure 300 in the safety membrane structure provided in this embodiment, which has a smaller area, so that the total capacitance of the film capacitor is larger, achieving a balance between the total capacitance and the self-healing capacitance loss of the film capacitor, and improving the capacity performance of the film capacitor.

[0025] Among them, the transverse segments 316 in any two adjacent first gaps 311 are arranged flush along the length direction of the insulating base film 100; in the insulating gap portion 310, the transverse segments 316 in the first gap 311 and the transverse segments 316 in the second gap 312 are aligned in the length direction of the insulating base film 100.

[0026] The spacing D3 between the transverse sections 316 in any two adjacent first gaps 311 is 0.1-0.3 mm, which is the length of the second fuse 314. The spacing D4 between the transverse sections 316 in any two adjacent second gaps 312 is 0.1-0.3 mm, which is the length of the third fuse 315. The sizes of D3 and D4 can be the same or different.

[0027] The height of the horizontal section 316 in the first gap 311 is 0.1-0.3 mm, the length of the vertical section 317 in the first gap 311 is 0.1-0.3 mm, the height of the horizontal section 316 in the second gap 312 is 0.1-0.3 mm, and the length of the vertical section 317 in the second gap 312 is 0.1-0.3 mm. In this way, the insulating gap structure 300 can have a good insulation effect while also making the total capacitance of the film capacitor as large as possible.

[0028] In some embodiments of the present application, the first gap 311 is located in the middle of the metal plating layer 200, the distance from the transverse section 316 in the first gap 311 to the blank area 102 is D1, the distance from the transverse section 316 in the second gap 312 to the blank area 102 is D2, and 0.4≤D2 / D1≤0.5. When 0.4≤D2 / D1≤0.5, the height of the second electrode unit 120 is slightly greater than the height of the third electrode unit 130, so that the area of ​​the second electrode unit 120 is slightly greater than the area of ​​the third electrode unit 130.

[0029] In this embodiment, based on the condition of the same size of the metal coating 200, the self-healing capacitance loss of the thin film capacitor can be set as small as possible and the total capacitance of the thin film capacitor can be set as large as possible, while the second electrode unit 120 can occupy the middle area of ​​the metal coating 200 to the maximum extent, thereby reducing the risk of the third electrode unit 130 being short-circuited and broken down.

[0030] In some embodiments of the present application, a conductive first fuse 313 is provided in the vertical section 317 in the second gap 312, and the first fuse 313 is conductively connected to the third electrode units 130 located on both sides thereof. Such a configuration can increase the current flow in the safety film structure and reduce the capacitance attenuation of the film capacitor.

[0031] The height of the first fuse portion 313 is 0.1-0.3 mm.

[0032] The first fuse part 313 may be a part of the metal plating layer 200 .

[0033] In some embodiments of the present application, the metal plating layer 200 is divided into a plurality of electrode units by the insulating gap structure 300, and the two electrode units between any two adjacent insulating gaps 310 are staggered along the length direction of the insulating base film 100. Such a setting can ensure that the current distribution in the electrode unit is relatively uniform.

[0034] In each insulating gap portion 310 , the two vertical segments 317 are staggered along the length direction of the insulating base film 100 , so that the two electrode units between two adjacent insulating gap portions 310 are staggered along the length direction of the insulating base film 100 .

[0035] Among them, in the two electrode units that are staggered, the distance between the same sides of the two electrode units is 0.6-1.2 mm.

[0036] The present application also provides a thin film capacitor, comprising the above-mentioned safety film structure.

[0037] It should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used above to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means more than three.

[0038] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A safety membrane structure, characterized in that: include: an insulating base film having a first long side; A metal plating layer, wherein the metal plating layer is arranged on the insulating base film, a blank area is formed between the metal plating layer and the first long side, an insulating gap structure is arranged in the metal plating layer, the height of the insulating gap structure is greater than half the height of the metal plating layer, the insulating gap structure includes a plurality of insulating gap portions arranged at intervals along the length direction of the insulating base film, the insulating gap portions include a first gap and a second gap, both of which are T-shaped, the second gap is located on a side of the first gap close to the first long side, the vertical section in the first gap is connected to the horizontal section in the second gap, the vertical section in the second gap extends to the blank area, the first gap is located in the middle of the metal plating layer, the distance from the horizontal section in the first gap to the blank area is D1, the distance from the horizontal section in the second gap to the blank area is D2, the D 2 / D1=0.5, the metal coating is divided into a plurality of electrode units by the insulating gap structure, a conductive first fuse is arranged in the vertical segment in the second gap, and the first fuse is conductively connected to the electrode units on both sides thereof, and any two adjacent transverse segments in the first gap are arranged flush along the length direction of the insulating base film; in the insulating gap portion, the transverse segments in the first gap and the transverse segments in the second gap are aligned in the height direction of the insulating base film, and any two adjacent transverse segments in the first gap have a partial metal coating between them, and the partial metal film is the second fuse, and any two adjacent transverse segments in the second gap also have a partial metal coating between them, and the partial metal film is the third fuse, and the second fuse and the third fuse are arranged relatively to each other along the height direction of the insulating base film.

2. The safety membrane structure according to claim 1, characterized in that: The metal plating layer is divided into a plurality of electrode units by the insulating gap structure, wherein the two electrode units between any two adjacent insulating gap portions are staggered along the length direction of the insulating base film.

3. The safety membrane structure according to claim 2, characterized in that: In the two electrode units that are staggered, the distance between the same sides of the two electrode units is 0.6-1.2 mm.

4. The safety membrane structure according to any one of claims 1 to 3, characterized in that: The spacing between any two adjacent transverse sections in the first gaps is 0.1-0.3 mm, and the spacing between any two adjacent transverse sections in the second gaps is 0.1-0.3 mm.

5. The safety membrane structure according to any one of claims 1 to 3, characterized in that: The height of the horizontal section in the first gap is 0.1-0.3mm, the length of the vertical section in the first gap is 0.1-0.3mm, the height of the horizontal section in the second gap is 0.1-0.3mm, and the length of the vertical section in the second gap is 0.1-0.3mm.

6. A film capacitor, characterized in that: It comprises a safety membrane structure according to any one of claims 1 to 5.

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