Thin film capacitor

Abstract

The utility model relates to a kind of film capacitors, the film capacitor includes capacitor core, capacitor core includes first electrode material layer, first dielectric material layer, second electrode material layer, wherein first dielectric material layer is located between first electrode material layer and second electrode material layer, including multilayer dielectric material film, the thickness of film is 7~20 μm, surface roughness RMS is greater than or equal to 1 μm, adjacent dielectric material film between, dielectric material film and first electrode material layer and second electrode material layer between are provided with insulating dielectric material. With multilayer surface roughening film as dielectric material, metal foil as electrode material, insulating dielectric material is arranged between layers, the problem of excessive smoothness of film surface, existence cavity and electric weak point is solved.

Description

Technical Field

[0001] This utility model belongs to the field of electronic components, specifically, it relates to a thin-film capacitor. Background Technology

[0002] Currently, the main dielectric materials for film capacitors include PP, PET, PEN, PS, PPS, PI, PEI, PEEK, and PTFE. These dielectric materials exhibit good dielectric properties; however, their high surface smoothness makes it difficult to deposit metallized electrodes. Furthermore, these materials often have numerous surface electrical weaknesses, excessive hardness, and poor flexibility. Therefore, film capacitors using these dielectric materials have not yet been widely adopted in the market, and related research is limited. Utility Model Content

[0003] To address the problems of existing technologies, this utility model proposes a thin-film capacitor, comprising a capacitor core. The capacitor core includes a first electrode material layer, a first dielectric material layer, and a second electrode material layer. The first dielectric material layer is disposed between the first electrode material layer and the second electrode material layer, comprising multiple dielectric material films. The thickness of the films is 7–20 μm, and the surface roughness RMS ≥ 1 μm. Insulating dielectric materials are provided between adjacent dielectric material films and between the dielectric material films and the first and second electrode material layers.

[0004] Preferably, the capacitor core further includes a second dielectric material layer, the first dielectric material layer and the second dielectric material layer are respectively disposed on both sides of the second electrode material layer, and the capacitor core is formed by winding the first electrode material layer, the first dielectric material layer, the second electrode material layer and the second dielectric material layer;

[0005] The first dielectric material layer and / or the second dielectric material layer include 2 to 5 dielectric material films, and an insulating dielectric material is provided between adjacent dielectric material films and between the dielectric material films and the second electrode material layer;

[0006] The dielectric material film is one of polytetrafluoroethylene (PTFE) film, polyimide (PI) film, polyetheretherketone (PEEK) film, and mica paper; and / or, the first electrode material layer and / or the second electrode material layer are aluminum foil or silver foil.

[0007] Preferably, the surface of the dielectric material film is subjected to surface roughening treatment to obtain the surface roughness;

[0008] Preferably, the insulating dielectric material is filled between adjacent dielectric material films and between the dielectric material films and the first electrode material layer and the second electrode material layer;

[0009] Preferably, the insulating medium material is epoxy resin, silicone resin, or polyurethane.

[0010] Preferably, the capacitor core is flat and round, with a thickness of 2 to 7 mm, an aspect ratio of (1.5 to 7):1, and a compression coefficient of 0.75 to 0.95.

[0011] Preferably, the first electrode material layer and / or the second electrode material layer include a plurality of electrode material segments arranged sequentially and electrically isolated from each other, each electrode material segment of the first electrode material layer and each electrode material segment of the second electrode material layer are at least partially staggered, and two electrode material segments located at the edges are used to connect to lead terminals to form a series capacitor structure.

[0012] The capacitor core is formed by winding the first electrode material layer, the first dielectric material layer, and the second electrode material layer.

[0013] The first dielectric material layer comprises 2 to 5 dielectric material films, wherein the dielectric material film is one of polytetrafluoroethylene (PTFE) film, polyimide (PI) film, polyetheretherketone (PEEK) film, and mica paper; and / or, the first electrode material layer and / or the second electrode material layer are aluminum foil or silver foil.

[0014] Preferably, the capacitor core further includes a bottom platform, on which lead terminals are vertically disposed as electrode leads.

[0015] The beneficial effects of this invention lie in solving the problem of excessively smooth film surfaces by roughening the dielectric material film. By using a multilayer dielectric film as the dielectric material, metal foil as the electrode material, and impregnation with an insulating dielectric material, the problems of voids and electrical weaknesses in the dielectric film are solved. This invention also provides a design scheme for a multi-capacitor structure with series-connected film capacitors, making high-voltage applications possible.

[0016] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.

[0018] Figure 1 The capacitor core material layer of a thin-film capacitor according to an embodiment of the present invention is shown.

[0019] Figure 2The capacitor core material layer of a thin-film capacitor according to another embodiment of the present invention is shown.

[0020] Figure 3 The capacitor core material layer of a thin-film capacitor according to another embodiment of the present invention is shown.

[0021] Figure 4 The appearance of the capacitor core of a thin-film capacitor according to one embodiment of the present invention is shown.

[0022] Figure 5 The capacitor core material layer of a thin-film capacitor according to yet another embodiment of the present invention is shown.

[0023] Figure 6 A schematic diagram of the internal series capacitor core according to an embodiment of the present invention is shown.

[0024] Figure 7 A schematic diagram of a method for manufacturing a thin-film capacitor according to an embodiment of the present invention is shown.

[0025] Explanation of reference numerals in the attached figures

[0026] 1-First electrode material layer; 2-First dielectric material layer; 3-Second electrode material layer; 4-Second dielectric material layer; 5-Capacitor core; 6-Bottom platform; 7-Lead terminal; 8-Insulating dielectric material. Detailed Implementation

[0027] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0028] refer to Figures 1 to 4 This utility model proposes a thin film capacitor, including a capacitor core 5. The capacitor core includes a first electrode material layer 1, a first dielectric material layer 2, and a second electrode material layer 3. The first dielectric material layer 2 is disposed between the first electrode material layer 1 and the second electrode material layer 3, and includes a multilayer dielectric material thin film with a thickness of 7 to 20 μm and a surface roughness RMS ≥ 1 μm.

[0029] The capacitor core also includes a second dielectric material layer 4. The first dielectric material layer 2 and the second dielectric material layer 4 are respectively disposed on both sides of the second electrode material layer 3. The capacitor core is formed by winding the first electrode material layer 1, the first dielectric material layer 2, the second electrode material layer 3, and the second dielectric material layer 4. An insulating dielectric material 8 is provided between adjacent dielectric material films and between the dielectric material films and the first and second electrode material layers.

[0030] In this embodiment, both the first dielectric material layer 2 and the second dielectric material layer 4 comprise 2 to 5 dielectric material thin films. For example... Figure 2 As shown, the black portion represents the electrode material layer, and the white portion represents the dielectric material layer. Both the first dielectric material layer 2 and the second dielectric material layer 4 consist of two dielectric material thin films. Figure 3 As shown, the black part represents the electrode material layer, and the white part represents the dielectric material layer. The first dielectric material layer 2 and the second dielectric material layer 4 both include three dielectric material thin films. Figure 2 and Figure 3 The number of thin film layers contained in the dielectric material layer is used only to indicate the number of thin film layers. For simplicity, the roughened surface of the thin film and the insulating dielectric material between the layers are not shown. The thickness and number of dielectric film layers can be selected within the range described herein, based on the capacitor voltage and capacitance, and the overall performance of the dielectric material.

[0031] The dielectric material film is one of polytetrafluoroethylene (PTFE) film, polyimide (PI) film, polyetheretherketone (PEEK) film, or mica paper. Preferably, the dielectric material film is PTFE film because it possesses superior dielectric strength, tensile strength, breakdown voltage, loss rate, and frequency characteristics. Specifically, the PTFE film has a dielectric constant of 2.0, a breakdown voltage as high as 800 V / μm, a loss as low as 0.0002, and maintains stable dielectric properties over a wide temperature range of -200℃ to 260℃.

[0032] The surface of the dielectric material film is roughened to obtain the surface roughness.

[0033] Preferably, the insulating dielectric material 8 is filled between adjacent dielectric material films and between the dielectric material film and the electrode material layer by impregnation. In order to fill the gaps between adjacent layers with the insulating dielectric material 8, the core is impregnated in a vacuum environment for 8 to 10 hours, at a temperature of 55°C to 85°C, and at a vacuum level of 1 to 5 Pa.

[0034] Alternatively, an insulating dielectric material layer can be pre-coated onto the surface of the dielectric material film.

[0035] Preferably, the insulating medium material is a pure organic polymer material, free of inorganic fillers. The heat resistance grade of the insulating medium material is F or H, the viscosity is less than 9000 Pa·s, and the pre-curing temperature is higher than 85°C. Preferably, the insulating medium material is epoxy resin, silicone resin, or polyurethane.

[0036] In this embodiment, the first electrode material layer 1 and the second electrode material layer 2 are aluminum foil or silver foil.

[0037] Preferably, the capacitor core 5 is formed into a flat circle by winding a first electrode material layer 1, a first dielectric material layer 2, a second electrode material layer 3, and a second dielectric material layer 4, with a thickness of 2 to 7 mm, an aspect ratio of (1.5 to 7):1, and a compression coefficient of 0.75 to 0.95.

[0038] The formula for calculating the compression coefficient is as follows:

[0039] K = (n*δ) / a

[0040] in:

[0041] n: The total number of dielectric thin film layers in the element.

[0042] δ: Thickness of a single-layer dielectric material film (e.g., μm).

[0043] a: Height (thickness) of the flattened component (e.g., mm).

[0044] like Figure 4 As shown, in this embodiment, the capacitor core also includes a bottom platform 6, on which lead terminals 7 are vertically disposed as electrode leads. The bottom platform 6 ensures the verticality of the lead terminals 7.

[0045] Film capacitors can consist of a core group composed of multiple capacitor cores. Several layers of insulating tape are wrapped around the outside of the core group, with the tape width exceeding the length of the capacitor core. High-temperature resistant insulating material is poured into both ends of the core group.

[0046] In addition, such as Figure 5 As shown, a series design can be used inside the film capacitor to increase the voltage of the film capacitor. The internal voltage distribution can be made uniform by controlling the winding length and number of turns of the film.

[0047] Specifically, the first electrode material layer and the second electrode material layer may include a plurality of electrode material segments arranged sequentially and electrically isolated from each other. Each electrode material segment of the first electrode material layer and each electrode material segment of the second electrode material layer are at least partially staggered, and the two electrode material segments located at the edges are connected to the lead terminals to form a series capacitor structure. Figure 5 A schematic diagram of a capacitor core with different series configurations is shown. In the diagram, black lines represent electrode material layers, white stripes between black lines represent dielectric material layers, and vertical bars represent lead-out electrodes. Figure 5 As shown, the first electrode material layer, the second electrode material layer, or both electrode material layers include multiple electrode material segments arranged sequentially and electrically isolated from each other, with adjacent electrode material segments separated by insulating strips. Depending on the number of electrode material segments provided, electrodes are led out from two electrode material segments at the edges of the same or different electrode material layers and connected to lead terminals, which is easily understood by those skilled in the art.

[0048] In this embodiment, similarly, the first dielectric material layer comprises multiple dielectric film layers with a thickness of 7–20 μm and a surface roughness RMS ≥ 1 μm. Insulating dielectric material is filled between adjacent dielectric film layers and between the dielectric film layers and the first and second electrode material layers. The capacitor core is formed by winding the first electrode material layer, the first dielectric material layer, and the second electrode material layer. The first dielectric material layer comprises 2 to 5 dielectric film layers, wherein the dielectric film is one of polytetrafluoroethylene (PTFE) film, polyimide (PI) film, polyetheretherketone (PEEK) film, or mica paper; and / or, the first electrode material layer and / or the second electrode material layer are aluminum foil or silver foil.

[0049] Another aspect of this utility model provides a method for manufacturing a thin-film capacitor, comprising:

[0050] A dielectric material film with a thickness of 7 to 20 μm is provided, and the surface of the dielectric material film is roughened to make its surface roughness RMS ≥ 1 μm. A first dielectric material layer and a second dielectric material layer are formed by using multilayer dielectric material films.

[0051] Provide a first electrode material layer and a second electrode material layer;

[0052] The first electrode material layer, the first dielectric material layer, the second electrode material layer, and the second dielectric material layer are stacked in sequence and wound into a core;

[0053] The core is immersed in an insulating dielectric material;

[0054] The impregnated core is heated to cure the insulating dielectric material.

[0055] In this embodiment, the core is impregnated in a vacuum environment for 8-10 hours at a temperature of 55°C-85°C, with a vacuum level of 1-5 Pa. Preferably, impregnation is performed in a vacuum impregnation apparatus, and the core must be atmospherically dried before impregnation. Preferably, the insulating dielectric material is epoxy resin, silicone resin, or polyurethane.

[0056] In this embodiment, the vacuum-impregnated core is placed on a mold for fixation and heated to cure the insulating dielectric material.

[0057] Finally, insulating tape is wrapped around the outside of the capacitor core, and high-temperature resistant insulating material is poured into both ends of the capacitor core.

[0058] Another aspect of this utility model provides a method for manufacturing a thin-film capacitor, comprising:

[0059] A dielectric material film with a thickness of 7 to 20 μm is provided, and the surface of the dielectric material film is roughened to make its surface roughness RMS ≥ 1 μm. The first dielectric material layer is formed by using a multilayer dielectric material film.

[0060] A first electrode material layer and a second electrode material layer are provided, wherein the first electrode material layer and / or the second electrode material layer comprises a plurality of electrode material segments arranged sequentially and electrically isolated from each other;

[0061] A first electrode material layer, a first dielectric material layer, and a second electrode material layer are stacked sequentially, with each electrode material segment of the first electrode material layer and each electrode material segment of the second electrode material layer being at least partially staggered, and the first electrode material layer, the first dielectric material layer, and the second electrode material layer are wound into a core.

[0062] The core is immersed in an insulating dielectric material;

[0063] The impregnated core is heated to cure the insulating dielectric material.

[0064] Similarly, in this embodiment, the core is impregnated in a vacuum environment for 8-10 hours at a temperature of 55°C-85°C, with a vacuum level of 1-5 Pa. Preferably, impregnation is performed in a vacuum impregnation apparatus, and the core must be atmospherically dried before impregnation. Preferably, the insulating dielectric material is epoxy resin, silicone resin, or polyurethane.

[0065] In this embodiment, the vacuum-impregnated core is placed on a mold for fixation and heated to cure the insulating dielectric material.

[0066] Finally, insulating tape is wrapped around the outside of the capacitor core, and high-temperature resistant insulating material is poured into both ends of the capacitor core.

[0067] Example 1

[0068] A PTFE film with a surface roughness of RMS 1.0 was prepared by plasma roughening of a PTFE film with a thickness of 10 μm. Two PTFE films were overlapped to form a first dielectric material layer and a second dielectric material layer, respectively. Aluminum foil was used as the first electrode material layer and the second electrode material layer.

[0069] The first electrode material layer, the first dielectric material layer, the second electrode material layer, and the second dielectric material layer are stacked sequentially and wound into a core. The capacitor core is then flattened into a flattened oval shape with a thickness of 5 mm and an aspect ratio of 3:1 using a hot-pressing process.

[0070] The capacitor core is impregnated with epoxy resin using a vacuum impregnation process. The impregnation temperature is set to 80℃, the vacuum degree is set to 1Pa, and the impregnation time is 9 hours.

[0071] After impregnation, the capacitor core is heat-treated to cure the epoxy resin. The heat treatment temperature is 150℃ and the heat treatment time is 36 hours.

[0072] The capacitor core's external electrode is fabricated using a tin-immersion process. Lead terminals are then soldered to the center of the external electrode.

[0073] The capacitor casing is wrapped with 5 turns of insulating tape, the width of which exceeds the capacitor core by 5mm. Epoxy resin is then injected into both ends to form a film capacitor.

[0074] Example 2

[0075] A PTFE film with a surface roughness of RMS 1.2 was prepared by plasma roughening of a PTFE film with a thickness of 12 μm. Three layers of PTFE film were stacked to form the first dielectric material layer and the second dielectric material layer, respectively. Aluminum foil was used as the first electrode material layer and the second electrode material layer.

[0076] The first electrode material layer, the first dielectric material layer, the second electrode material layer, and the second dielectric material layer are stacked sequentially, according to... Figure 6 The figure shows two capacitor cores wound together in series. In the figure, the black stripes represent the electrode material layer, and the white stripes between the black lines represent the dielectric material layer. The capacitor cores are flattened into a flattened oval shape with a thickness of 6mm and an aspect ratio of 3:2 using a hot-pressing process.

[0077] The capacitor core is impregnated with epoxy resin using a vacuum impregnation process. The impregnation temperature is set to 80℃, the vacuum degree is set to 1Pa, and the impregnation time is 10h.

[0078] After impregnation, the capacitor core is heat-treated to cure the epoxy resin. The heat treatment temperature is 150℃ and the heat treatment time is 36 hours.

[0079] The capacitor core's external electrode is fabricated using a tin-immersion process. Lead terminals are then soldered to the center of the external electrode.

[0080] The capacitor casing is wrapped with 5 turns of insulating tape, the width of which exceeds the capacitor core by 5mm. Epoxy resin is then injected into both ends to form a film capacitor.

[0081] Example 3

[0082] like Figure 7 As shown, a multilayer PTFE film is used as the dielectric material layer, and aluminum foil is used as the electrode material layer. The aluminum foil is 80mm wide, and the film is 100mm wide. The aluminum foil is placed in the middle of the PTFE film, leaving gaps on both sides and at both ends of the film. Figure 7The inner and outer loop count areas are shown. Two flag-shaped lead-out foils are made from aluminum foil.

[0083] From bottom to top, the first dielectric material layer, the first electrode material layer, the second dielectric material layer, and the second electrode material layer are stacked sequentially. First, the multilayer PTFE film is wound 5 turns, then each stacked layer is wound 10 turns. A flag-shaped lead-out foil is placed on the aluminum foil, and the flag-shaped lead-out foil is ultrasonically spot-welded to the aluminum foil. Then, the upper foil is cut, the film is wound 2 turns, the upper foil is continued, and a flag-shaped lead-out foil is placed on the aluminum foil, and the flag-shaped lead-out foil is ultrasonically spot-welded to the aluminum foil. Then, the PTFE film and aluminum foil are wound 7.25 turns, the upper and lower aluminum foils are cut, and then several more turns of PTFE film are wound.

[0084] The capacitor core is flattened into a flat oval shape with a thickness of 6mm and an aspect ratio of 3:2.

[0085] The capacitor core is impregnated with epoxy resin using a vacuum impregnation process. The impregnation temperature is set to 80℃, the vacuum degree is set to 1Pa, and the impregnation time is 10h.

[0086] After impregnation, the capacitor core is heat-treated to cure the epoxy resin. The heat treatment temperature is 150℃ and the heat treatment time is 36 hours.

[0087] The capacitor core's external electrode is fabricated using a tin-immersion process. Lead terminals are then soldered to the center of the external electrode.

[0088] The capacitor casing is wrapped with five turns of insulating tape, the tape being 5mm wider than the capacitor core. Epoxy resin is then poured into both ends to form the capacitor. Testing showed that the capacitor's breakdown voltage reached 10kV.

[0089] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A thin-film capacitor, characterized in that, The capacitor core includes a first electrode material layer, a first dielectric material layer, and a second electrode material layer. The first dielectric material layer is disposed between the first electrode material layer and the second electrode material layer. The capacitor core includes multiple dielectric film layers with a thickness of 7~20μm and a surface roughness RMS≥1μm. An insulating dielectric material is provided between adjacent dielectric film layers and between the dielectric film layers and the first and second electrode material layers.

2. The thin-film capacitor according to claim 1, characterized in that, The capacitor core further includes a second dielectric material layer, and the first dielectric material layer and the second dielectric material layer are respectively disposed on both sides of the second electrode material layer. The capacitor core is formed by winding the first electrode material layer, the first dielectric material layer, the second electrode material layer, and the second dielectric material layer. The first dielectric material layer and / or the second dielectric material layer include 2 to 5 dielectric material films, and an insulating dielectric material is provided between adjacent dielectric material films and between the dielectric material films and the second electrode material layer; The dielectric material film is one of polytetrafluoroethylene (PTFE) film, polyimide (PI) film, polyetheretherketone (PEEK) film, and mica paper; and / or, the first electrode material layer and / or the second electrode material layer are aluminum foil or silver foil.

3. The thin-film capacitor according to claim 1 or 2, characterized in that, The surface of the dielectric material film is roughened to obtain the surface roughness.

4. The thin-film capacitor according to claim 1, characterized in that, The insulating dielectric material is filled between adjacent dielectric material films and between the dielectric material films and the first and second electrode material layers by impregnation.

5. The thin-film capacitor according to claim 1, characterized in that, The insulating medium material is epoxy resin, silicone resin, or polyurethane.

6. The thin-film capacitor according to claim 1, characterized in that, The capacitor core is flat and round, with a thickness of 2-7 mm, an aspect ratio of (1.5-7):1, and a compression coefficient of 0.75-0.

95.

7. The thin-film capacitor according to claim 1, characterized in that, The first electrode material layer and / or the second electrode material layer include a plurality of electrode material segments arranged sequentially and electrically isolated from each other. Each electrode material segment of the first electrode material layer and each electrode material segment of the second electrode material layer are at least partially staggered, and two electrode material segments located at the edges are used to connect to lead terminals to form a series capacitor structure. The capacitor core is formed by winding the first electrode material layer, the first dielectric material layer, and the second electrode material layer. The first dielectric material layer comprises 2 to 5 dielectric material films, wherein the dielectric material film is one of polytetrafluoroethylene (PTFE) film, polyimide (PI) film, polyetheretherketone (PEEK) film, and mica paper; and / or, the first electrode material layer and / or the second electrode material layer are aluminum foil or silver foil.

8. The thin-film capacitor according to claim 1, characterized in that, The capacitor core also includes a bottom platform, on which lead terminals are vertically arranged as electrode leads.

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