A three-dimensional wound film capacitor

Abstract

This invention relates to the field of capacitor technology, specifically to a three-dimensional wound film capacitor, comprising multiple flexible dielectric films and two metal electrode layers; the flexible dielectric film includes an intermediate dielectric film and at least one insulating dielectric film; the two metal electrode layers are respectively attached to both sides of the intermediate dielectric film; etched slots are provided on the metal electrode layers; the etched slots are distributed on the surface of the metal electrode layers according to a preset arrangement to form an etched pattern; the preset arrangement can be periodic or non-periodic; the insulating dielectric film is attached to the side of the metal electrode layers opposite to the intermediate dielectric film; the two metal electrode layers and the attached multiple flexible dielectric films are wound together to form a three-dimensional wound structure. This invention improves the high-frequency electrical performance, structural stability, and application adaptability of the capacitor by optimizing the electrode etching structure, dielectric layering structure, and three-dimensional winding form.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and more specifically to a three-dimensional wound film capacitor. Background Technology

[0002] With the rapid iteration of modern electronic technology, electronic devices are constantly developing towards higher integration, miniaturization, and higher frequency and speed. Circuit operating frequencies are continuously rising, and problems such as electromagnetic interference and signal crosstalk during equipment operation are becoming increasingly serious. Electromagnetic compatibility (EMC) performance has become a core factor restricting the stability and reliability of equipment in fields such as precision electronics, high-frequency communication, and new energy industrial control. Capacitors, as core passive components in circuits, are widely used in filtering, power supply decoupling, and transient interference suppression, and are key components for ensuring the electromagnetic performance of circuits. Traditional parallel-plate capacitors use an integrated metal plate structure, whose electric field energy density is limited by the electrode area and dielectric thickness. At the same time, this structure generates a large parasitic inductance (ESL) under high-frequency operating conditions, causing a significant decrease in high-frequency filtering performance and making it difficult to meet the requirements of high-frequency circuits.

[0003] Currently, the industry has confirmed that by etching defect grounds and fractal patterns on the electrode surface, distributed inductance and capacitance can be introduced, effectively optimizing the frequency response of transmission lines. This technology is currently mostly applied to planar transmission lines and cable shielding layers, such as using fractal patterns to fabricate filter cables and low-pass filters. Most existing fractal electrode capacitors on the market still use a planar electrode system, primarily replacing traditional interdigitated electrodes with fractal structures. The design focuses on maximizing the electrode edge length within a two-dimensional plane to increase capacitance density per unit area, and these products are mostly used in the field of micro supercapacitors. Meanwhile, although planar fractal capacitors can increase capacitance density per unit area, they are limited by two-dimensional space, preventing the full utilization of edge effects and resulting in significant shortcomings in space utilization. Summary of the Invention

[0004] Therefore, the present invention provides a three-dimensional wound film capacitor, which aims to solve the technical problems of high high-frequency loss, poor transient response, simple structure, weak adaptability and insufficient stability of film capacitors in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] According to a first aspect of the present invention, the present invention provides a three-dimensional wound film capacitor, comprising a multilayer flexible dielectric film and two metal electrode layers; The flexible dielectric film comprises an intermediate dielectric film and at least one insulating dielectric film; The two metal electrode layers are respectively attached to both sides of the intermediate dielectric film; the metal electrode layers are provided with etching slots; the etching slots are distributed on the surface of the metal electrode layers in a preset arrangement to form an etching pattern; The insulating dielectric film is attached to the side of the metal electrode layer opposite to the intermediate dielectric film; The two metal electrode layers and the attached multilayer flexible dielectric film are wound together to form a three-dimensional winding structure.

[0007] Furthermore, the insulating medium film is one or two layers; When the insulating dielectric film is a single layer, the insulating dielectric film is disposed on the outermost side of the three-dimensional winding structure.

[0008] Furthermore, end electrodes are respectively provided at both ends of the three-dimensional winding structure along its axial direction; The terminal electrode is formed by metal spraying or wire bonding.

[0009] Furthermore, the two metal electrode layers include a first metal electrode layer and a second metal electrode layer; The upper edge of the first metal electrode layer is recessed relative to the flexible dielectric film; the lower edge of the second metal electrode layer is recessed relative to the flexible dielectric film.

[0010] Furthermore, the etched gaps have a fractal structure; The fractal structure includes at least one of Hilbert fractals, Koch fractals, Peano fractals, and Minkowski fractals; the iteration order of the fractal structure is 1 to 5.

[0011] Furthermore, the hollowed-out areas of the etched seams are filled with insulating material; The insulating material includes either polytetrafluoroethylene or polyimide.

[0012] Furthermore, the flexible dielectric film is made of any one of polyimide, liquid crystal polymer, polyethylene terephthalate, and polyethylene naphthalate.

[0013] Furthermore, the metal electrode layer is made of any one of copper, aluminum, silver, and metal alloys.

[0014] Furthermore, the three-dimensional winding structure is any one of a cylindrical winding body, a capsule-shaped cylindrical winding body, and an elliptical cylindrical winding body; the number of winding turns is 2 or more.

[0015] Furthermore, the geometric parameters of the etched gap are determined based on preset electrical performance indicators and using capacitance testing technology and / or transient response characteristic testing technology. The preset electrical performance indicators include insertion loss, return loss, and / or transient response characteristics at the target frequency band; the geometric parameters include at least one of the following: slot width, slot length, and fractal order.

[0016] The present invention, by adopting the above technical solution, has at least the following beneficial effects: This invention proposes a three-dimensional wound film capacitor, comprising multiple flexible dielectric films and two metal electrode layers. The flexible dielectric films include at least one intermediate dielectric film and at least one insulating dielectric film. The two metal electrode layers are respectively attached to both sides of the intermediate dielectric film. Etched slots are provided on the metal electrode layers. These etched slots are distributed on the surface of the metal electrode layers according to a predetermined arrangement, forming an etched pattern. The predetermined arrangement can be periodic or aperiodic. The insulating dielectric film is attached to the side of the metal electrode layers facing away from the intermediate dielectric film. The two metal electrode layers and the attached multiple flexible dielectric films are wound together to form a three-dimensional wound structure. This invention utilizes the etched slots on the electrode plates to introduce distributed inductance and capacitance, combined with the multidirectional electric field coupling generated by the three-dimensional winding configuration, significantly improving the high-frequency performance and transient energy management capability of the capacitor.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A simplified schematic diagram of a three-dimensional winding structure (cylindrical winding body) provided in an embodiment of the present invention is shown; Figure 2 A simplified schematic diagram of a three-dimensional winding structure (capsule-shaped columnar winding) provided in another embodiment of the present invention is shown; Figure 3 A simplified schematic diagram of a three-dimensional winding structure (elliptical cylindrical winding) provided in another embodiment of the present invention is shown; Figure 4 A simplified schematic diagram of a flattened three-dimensional winding structure provided in an embodiment of the present invention is shown; Figure 5 A schematic diagram of the unfolded metal electrode layer with an etched gap having a second-order Hilbert fractal structure is shown in an embodiment of the present invention. Figure 6 This invention provides a schematic diagram of the basic unit of Hilbert fractal structures with different iteration orders according to an embodiment of the present invention. Figure 7 This invention provides a schematic diagram of the basic unit of a KOCH fractal structure with different iteration orders according to an embodiment of the present invention. Figure 8 This invention provides a schematic diagram of the basic unit of a Peano fractal structure with different iteration orders according to an embodiment of the present invention. Figure 9 This diagram shows an unfolded schematic of a metal electrode layer with an etched slot featuring a Minkowski fractal structure, according to an embodiment of the present invention. Figure 10 The diagram shows the test results of the S21 parameter curves corresponding to different fractal orders provided in an embodiment of the present invention. Detailed Implementation

[0020] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0022] This invention provides a three-dimensional wound film capacitor, comprising a multilayer flexible dielectric film and two metal electrode layers.

[0023] The flexible dielectric film comprises an intermediate dielectric film and at least one insulating dielectric film. Two metal electrode layers are attached to both sides of the intermediate dielectric film, and the insulating dielectric film is attached to the side of the metal electrode layers facing away from the intermediate dielectric film. The two metal electrode layers and the attached multilayer flexible dielectric films are wound together to form a three-dimensional winding structure.

[0024] like Figure 1 The image shown is a simplified schematic diagram of a three-dimensional wound structure (cylindrical wound body). From... Figure 1 As can be seen, the three-dimensional winding structure consists of a top layer of insulating dielectric film 5 for top protection, a top metal electrode layer 3, an intermediate dielectric film 1 for isolating the two metal electrode layers, a bottom metal electrode layer 2, and a bottom layer of insulating dielectric film 4 for bottom protection. The multiple films are attached to each other to form a sandwich structure, and then wound together (with two or more turns) to form a cylindrical winding structure, i.e., a cylindrical winding body.

[0025] Figure 1 The three-dimensional winding structure shown has two layers of insulating dielectric film to isolate the metal electrode layer during winding and prevent short circuits. In practical applications, the insulating dielectric film can also be a single layer. When the insulating dielectric film is a single layer, it is placed on the outermost side of the three-dimensional winding structure (i.e., retaining the insulating dielectric film 5 for top layer protection), fully covering and protecting the exposed top metal electrode layer 3. This effectively blocks the metal electrodes between the winding turns, significantly reducing the risk of electrode overlap, leakage, and short circuits, while also improving the overall structure's wear resistance and operational stability.

[0026] Preferably, the flexible dielectric film in the embodiments of the present invention can be made of any one of polyimide, liquid crystal polymer, polyethylene terephthalate, and polyethylene naphthalate; the metal electrode layer can be made of any one of copper, aluminum, silver, and metal alloys.

[0027] Furthermore, end electrodes (not shown in the figure) are respectively provided at both ends of the three-dimensional winding structure. The external circuit can be connected to the top metal electrode layer 3 on the lower side of the three-dimensional winding structure and to the bottom metal electrode layer 2 on the upper side of the three-dimensional winding structure by spraying silver paste and welding leads.

[0028] In an optional embodiment, the three-dimensional winding structure can also employ a capsule-shaped cylindrical winding or an elliptical cylindrical winding. For example... Figures 2-3The figures shown are simplified schematic diagrams of capsule-shaped cylindrical windings and elliptical cylindrical windings, respectively. The cylindrical winding is the basic structure, with a regular shape, mature winding process, convenient mass production, and more controllable costs. It features uniform circumferential stress, tight bonding of multiple thin films, good structural consistency, and adaptability to various standard circular mounting positions, making it more versatile. The capsule-shaped cylindrical winding has rounded ends and a straight middle section, resulting in the smoothest end-face transition. This further weakens the end electric field, provides better insulation protection for the end electrode areas, and facilitates axial limiting and clamping positioning, making it suitable for scenarios requiring axial fixation. The elliptical cylindrical winding has an elliptical cross-section, resulting in higher radial space utilization. It occupies less space than a circular cross-section in flat or long mounting slots, adapts to flat structure designs, has a uniform inter-turn contact area distribution, and better heat dissipation. In practical applications, cylindrical, capsule-shaped, or elliptical cylindrical winding structures can be flexibly selected according to the product's installation space dimensions, assembly conditions, withstand voltage index, and heat dissipation requirements to adapt to different application scenarios and maximize the capacitor's insulation reliability, structural stability, and environmental adaptability.

[0029] Furthermore, in this embodiment of the invention, etched gaps are provided on the metal electrode layer. The etched gaps are distributed on the surface of the metal electrode layer in a preset arrangement (either periodic or non-periodic) to form an etched pattern. The hollowed-out areas of the etched gaps can be completely hollowed out or filled with insulating material (such as polytetrafluoroethylene, polyimide, etc.) to adjust the dielectric environment.

[0030] like Figure 4 The diagram shown is a simplified schematic of the flattened three-dimensional winding structure. The multilayer thin films, from top to bottom, are: top layer insulating dielectric film 5 (thickness H=50μm), top layer metal electrode layer 3 (thickness d1=18μm), middle dielectric film 1 (thickness d2=127μm), bottom layer metal electrode layer 2 (thickness d1=18μm), and bottom layer insulating dielectric film 4 (thickness H=50μm). Figure 4 As can be seen, the upper edge of the top metal electrode layer 3 is recessed relative to the flexible dielectric film, and the lower edge of the bottom metal electrode layer 2 is also recessed relative to the flexible dielectric film. By leaving gaps between the edges of the metal electrode layers and the flexible dielectric film, overlap and short circuits of the metal electrodes in the same turn or adjacent turns after winding are prevented.

[0031] Figure 4 It can also be seen that both the top metal electrode layer 3 and the bottom metal electrode layer 2 have etched the Hilbert fractal structure's etch gaps. For example... Figure 5 The figure shows a schematic diagram of the unfolded metal electrode layer with an etched gap containing a second-order Hilbert fractal structure (6 in the figure is a basic unit).

[0032] This invention significantly improves capacitor performance by introducing fractal-structured etched slots into a metal electrode layer and combining them with a three-dimensional winding structure. Specifically, the fractal structure, due to its inherent self-similarity and space-filling properties, can significantly increase the effective boundary length of the electrode within a limited electrode area. When this metal electrode layer with fractal-structured etched slots is wound together with a flexible dielectric film into a three-dimensional winding structure, the electric field generated by the etched slots undergoes complex mutual coupling in the radial, tangential, and axial directions. This three-dimensional electric field "folding" and "reshaping" effect effectively introduces distributed inductance and capacitance within the capacitor.

[0033] Furthermore, such as Figure 6 The diagram shows the basic unit of Hilbert fractal structures with different iteration orders. In the diagram, 61 represents a first-order Hilbert fractal structure, 62 a second-order Hilbert fractal structure, 63 a third-order Hilbert fractal structure, and 64 a fourth-order Hilbert fractal structure. The construction of the Hilbert fractal structure follows a recursive rule: for an n-order Hilbert curve, the target square region is first divided into virtual grids, each with a side length of d. Then, the center points of all grids are connected sequentially through a specific path, forming a continuous polygonal line that traverses each grid exactly once, thus completely filling the entire square region. As the order n increases, the grid division becomes more refined, and the total length of the curve increases exponentially.

[0034] Therefore, by combining the multi-order resonant characteristics of fractal slots, multiple transmission zeros can be generated over a wide frequency band, significantly improving the capacitor's insertion loss and out-of-band rejection capability, effectively suppressing electromagnetic interference. Simultaneously, this design increases capacitance density and enhances the capacitor's protection against strong transient interference such as nuclear electromagnetic pulses (HEMP) and electrostatic discharges (ESD). Furthermore, the tiny spacing of the fractal slots can generate micro-discharges under high-energy impacts, further reducing the impact amplitude and buffering the rising edge, thus providing stronger transient energy management capabilities.

[0035] In an alternative embodiment, the fractal structure may also employ Koch fractals, Peano fractals, and Minkowski fractals, in addition to Hilbert fractals. Figure 7 The diagram shows the basic unit of the KOCH fractal structure at different iteration orders. The sharp-cornered structure of the KOCH fractal can enhance local electric field distortion, making it easier to generate micro-discharge effects and providing stronger buffering and discharge capabilities against transient impacts. It is simple to implement, with regular line angles, making it suitable for laser etching or chemical etching. Figure 8The diagram shows the basic unit of the Peano fractal structure with different iteration orders. At the same order, the Peano fractal curve exhibits extremely high total gap length and path complexity, enabling the formation of a very dense distributed LC network within a finite area. Furthermore, the electric field coupling is more uniform, making it suitable for scenarios requiring wideband, multi-order filtering. Figure 9 The diagram shows the unfolded schematic of a metal electrode layer with etched seams featuring a Minkowski fractal structure (black lines represent the etched seams). The Minkowski fractal lines exhibit smooth transitions, weak electric field concentration, and superior insulation reliability and withstand voltage performance. In practical applications, Hilbert, Koch, Peano, or Minkowski fractal structures can be flexibly selected based on the device's target operating frequency band, withstand voltage level, transient protection requirements, and PCB / etching process limitations to achieve optimal filtering performance, insulation reliability, and process feasibility for specific scenarios.

[0036] To investigate the impact of different fractal orders on the total gap length within a fixed area, this embodiment of the invention uses a Hilbert fractal structure as an example, assuming the physical size of the capacitor unit is a square region of D×D=10mm×10mm. The region is divided into 2 n ×2 n Grid, grid side length d=D / 2 n The Hilbert fractal curve connects the centers of each grid sequentially, and its total length L total It can be approximated as:

[0037] Among them, L total (n) represents the total length of the electrode gap corresponding to the order n; d represents the grid side length; and D represents the capacitor cell side length.

[0038] Based on the above formula, L is calculated. total (1) Approximately 15mm, L total (2) Approximately 37.5 mm, L total (3) Approximately 78.75 mm, L total (4) Approximately 159.375 mm, L total (5) Approximately 319.6875 mm. It can be seen that as the order n increases, the total length of the electrode gap increases sharply, which provides a geometric theoretical basis for enhancing the edge effect and introducing series inductance.

[0039] When converting theoretical polygonal lines into actual etched patterns, a certain linewidth w needs to be assigned to the polygonal lines, and a spacing s needs to be maintained between adjacent line segments to avoid short circuits. The values ​​of linewidth w and spacing s are limited by the minimum linewidth / spacing capability of PCB manufacturing processes. In this embodiment of the invention, w=0.2mm and s=0.2mm are selected, from which it can be deduced that the grid side length d must satisfy d=w+s=0.4mm. However, for a given unit side length D=10 mm, if d=0.4 mm is required, then 2 n =D / d=25, i.e., n=log225≈4.64, which cannot be rounded down. Therefore, in this embodiment of the invention, electrodes corresponding to five orders of Hilbert fractal curve slots are designed for n=1, 2, 3, 4, and 5, with corresponding actual mesh side lengths d=5mm, 2.5mm, 1.25mm, 0.625mm, and 0.3125mm, respectively. For n=5, d=0.3125mm, the spacing s=dw=0.1125mm, which is still greater than the minimum line spacing of general PCB processes, meeting the manufacturing requirements. Therefore, the iteration order of the fractal structure is preferably 1 to 5.

[0040] Furthermore, in order to verify and investigate the influence of the fabrication scheme of the etched gap combined with the three-dimensional winding structure proposed in the embodiments of the present invention on the capacitor performance (such as frequency response characteristics, static capacitance and energy density), the embodiments of the present invention take the Hilbert fractal structure as an example, and establish the S21 parameter curves of capacitors of different fractal orders by radio frequency test and static capacitance test with the help of a network analyzer, clarify the performance differences of fractal structures of different orders, and verify the technical advantages of the present invention.

[0041] like Figure 10 The figure shows the test results of the S21 parameter curves corresponding to different fractal orders. The test results show that the frequency response characteristics of the device change significantly after adding the fractal etching structure. The resonant frequency of the 3rd order Hilbert fractal structure is 0.646 GHz, which is a higher frequency shift compared to 0.459 GHz without fractal blank capacitor. At this order, the gap size is larger, the equivalent metal electrode area is smaller, the electric field folding effect is weaker, and the impact on the overall performance is limited. When using the 4th and 5th order Hilbert fractal structures, the resonant frequencies drop to 0.37 GHz and 0.313 GHz, respectively, shifting to lower frequencies. At this time, the electric field folding effect is significantly enhanced, and the energy density of the device is significantly improved.

[0042] Meanwhile, the embodiment of the present invention also used the bridge method to conduct static capacitance tests. The test results show that in the three-dimensional wound structure, the capacitance value of the 0th order (without fractal structure) is 8.847nF, and the capacitance values ​​of the 3rd, 4th, and 5th order fractal structures are 3.342nF, 9.543nF, and 10.073nF, respectively; in the two-dimensional planar film structure without winding, the capacitance value of the 0th order is 2.7846nF, and the capacitance values ​​of the 3rd, 4th, and 5th order fractal structures are 7.394nF, 7.939nF, and 8.245nF, respectively.

[0043] Based on the combined results of the S21 parameter tests and static capacitance tests, it can be confirmed that: the fractal order can effectively control the frequency response characteristics and resonant frequency of the device; the fractal etching structure can effectively improve the static capacitance value of the capacitor, and the capacitance value is positively correlated with the total length of the fractal gap; the three-dimensional winding structure, combined with the fractal gap, can further increase the equivalent capacitance, exhibiting superior energy storage performance compared to planar film structures. These results validate the design advantages of this scheme and provide data support for structural parameter optimization. Specifically, in practical applications, the geometric parameters of the etched gap (gap width, gap length, and fractal order) can be determined based on preset electrical performance indicators (insertion loss, return loss, and / or transient response characteristics at the target frequency band) using capacitance testing technology and / or transient response characteristic testing technology. Experiments have verified that the capacitance value increases with the total gap length and decreases with the gap width; the transient breakdown voltage is positively correlated with the gap width. By iteratively optimizing the structure based on these parameter patterns, the design indicators for various geometric parameters can be accurately achieved.

[0044] This invention proposes a three-dimensional wound film capacitor, comprising multiple flexible dielectric films and two metal electrode layers; the flexible dielectric film includes an intermediate dielectric film and at least one insulating dielectric film; the two metal electrode layers are respectively attached to both sides of the intermediate dielectric film; etched slots are provided on the metal electrode layers; the etched slots are distributed on the surface of the metal electrode layers according to a predetermined arrangement to form an etched pattern; the predetermined arrangement can be periodic or non-periodic; the insulating dielectric film is attached to the side of the metal electrode layers opposite to the intermediate dielectric film; the two metal electrode layers and the attached multiple flexible dielectric films are wound together to form a three-dimensional wound structure. Compared with the prior art, this invention has at least the following beneficial effects: 1) By combining etched slots with a three-dimensional winding structure, the slot electric field can form multi-dimensional coupling in the radial, tangential, and axial directions, achieving three-dimensional folding and reshaping of electric field energy. Compared with planar fractal capacitors, this structure increases capacitance density by more than 50%. 2) Etched slots are arranged on the electrode plates, especially fractal slots, which can build a distributed inductor-capacitor network inside the device, enabling the product to maintain high insertion loss over a wide frequency range and have excellent electromagnetic interference suppression capabilities. 3) Fractal gaps possess multi-order resonance characteristics, which can generate multiple transmission zeros, significantly improving out-of-band suppression performance; at the same time, they can effectively resist strong transient interferences such as nuclear electromagnetic pulse (HEMP) and electrostatic discharge (ESD); 4) The fractal gaps are very small, which can generate a micro-discharge effect when subjected to high-energy impacts, attenuating the impact amplitude and smoothing the signal rise time, further enhancing the device's protection against strong transient interference. 5) The product is manufactured using flexible printed circuit board (FPCB) technology combined with roll-to-roll packaging. The technology is mature and stable, making it easy to mass-produce.

[0045] Those skilled in the art will clearly understand that the specific working process of the systems, devices, modules and units described above can be referred to the corresponding process in the foregoing method embodiments. For the sake of brevity, it will not be repeated here.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that within the spirit and principles of the present invention, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the corresponding technical solutions to depart from the protection scope of the present invention.

Claims

1. A three-dimensional wound film capacitor, characterized in that, It includes a multilayer flexible dielectric film and two metal electrode layers; The flexible dielectric film comprises an intermediate dielectric film and at least one insulating dielectric film; The two metal electrode layers are respectively attached to both sides of the intermediate dielectric film; the metal electrode layers are provided with etching slots; the etching slots are distributed on the surface of the metal electrode layers in a preset arrangement to form an etching pattern; The insulating dielectric film is attached to the side of the metal electrode layer opposite to the intermediate dielectric film; The two metal electrode layers and the attached multilayer flexible dielectric film are wound together to form a three-dimensional winding structure.

2. The three-dimensional wound film capacitor according to claim 1, characterized in that, The insulating medium film is one or two layers; When the insulating dielectric film is a single layer, the insulating dielectric film is disposed on the outermost side of the three-dimensional winding structure.

3. The three-dimensional wound film capacitor according to claim 1, characterized in that, The three-dimensional winding structure is provided with end electrodes at both ends of its axial direction. The terminal electrode is formed by metal spraying or wire bonding.

4. The three-dimensional wound film capacitor according to claim 1, characterized in that, The two metal electrode layers include a first metal electrode layer and a second metal electrode layer; The upper edge of the first metal electrode layer is recessed relative to the flexible dielectric film; the lower edge of the second metal electrode layer is recessed relative to the flexible dielectric film.

5. The three-dimensional wound film capacitor according to any one of claims 1 to 4, characterized in that, The etched gaps have a fractal structure; The fractal structure includes at least one of Hilbert fractals, Koch fractals, Peano fractals, and Minkowski fractals; the iteration order of the fractal structure is 1 to 5.

6. The three-dimensional wound film capacitor according to any one of claims 1 to 4, characterized in that, The hollowed-out areas of the etched seams are filled with insulating material; The insulating material includes either polytetrafluoroethylene or polyimide.

7. The three-dimensional wound film capacitor according to any one of claims 1 to 4, characterized in that, The flexible dielectric film is made of any one of polyimide, liquid crystal polymer, polyethylene terephthalate, and polyethylene naphthalate.

8. The three-dimensional wound film capacitor according to any one of claims 1 to 4, characterized in that, The metal electrode layer is made of any one of copper, aluminum, silver, or metal alloys.

9. The three-dimensional wound film capacitor according to any one of claims 1 to 4, characterized in that, The three-dimensional winding structure is any one of cylindrical winding, capsule-shaped cylindrical winding, and elliptical cylindrical winding; the number of winding turns is 2 or more.

10. The three-dimensional wound film capacitor according to any one of claims 1 to 4, characterized in that, The geometric parameters of the etched gap are determined based on preset electrical performance indicators and using capacitance testing technology and / or transient response characteristic testing technology. The preset electrical performance indicators include insertion loss, return loss, and / or transient response characteristics at the target frequency band; the geometric parameters include at least one of the following: slot width, slot length, and fractal order.

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