Preparation method of self-repairing thin film capacitor

Abstract

The invention discloses a preparation method of a self-repairing thin film capacitor, which comprises the following steps of: performing ultrasonic cleaning on a polymer thin film substrate by using deionized water, absolute ethyl alcohol and a surfactant solution in sequence, removing residual impurities on the surface, treating the surface of the substrate by using plasmas of mixed gas of oxygen and argon, and enhancing the surface polarity and chemical activity, thereby obtaining the self-repairing thin film capacitor. The treatment time is 60-90 seconds, a silane coupling agent is sprayed on the surface of the treated film to form a functional layer for enhancing the adhesive force, a conductive metal layer with the thickness of 10-50 nanometers is deposited on the surface of a base material through a magnetron sputtering method or an electron beam evaporation method, the conductive metal is aluminum, copper or silver, and the deposition rate and the film thickness uniformity are monitored in real time in the deposition process. When local breakdown occurs, the microcapsules release contents under the action of an electric field or a heat effect, a damaged area is rapidly filled, and a conductive path is reconstructed, so that rapid self-repairing of the capacitor is realized, the reliability of the capacitor is greatly improved, and the service life of the capacitor is greatly prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of film capacitors, and in particular to a method for preparing a self-repairing film capacitor. Background Art

[0002] As an important electronic component, film capacitors are widely used in various electronic devices, especially in the fields of power electronics, communication equipment and automotive electronics. One of the failure mechanisms of film capacitors is local breakdown, especially under high voltage or overload conditions. Local breakdown is usually caused by excessive electric field in certain areas of the dielectric material, resulting in material damage or defects in the dielectric itself. When the electric field strength in a local area of ​​the dielectric material exceeds its tolerance limit, the material will break down, resulting in current short circuit and local damage to the dielectric. This breakdown will not only cause the capacitor to lose its conductive properties, but also reduce its carrying capacity. In severe cases, it will cause the entire capacitor to fail. At present, most film capacitors cannot recover their conductive properties after local breakdown. This is mainly because traditional materials and designs lack effective self-repair mechanisms. After breakdown occurs, the internal circuit path of the capacitor is destroyed, and traditional dielectric materials cannot quickly recover their original insulation and conductive properties after breakdown. Therefore, once the capacitor encounters local breakdown, its performance cannot be restored, resulting in device failure and even having a serious impact on the stability of the entire circuit system. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the purpose of the present invention is to propose a method for preparing a self-healing thin film capacitor, which can introduce a microcapsule coating design containing a conductive material and a repair agent. When a local breakdown occurs, the microcapsule releases its contents under the action of an electric field or thermal effect, quickly fills the damaged area and rebuilds the conductive path, thereby achieving rapid self-repair of the capacitor and greatly improving its reliability and service life.

[0005] To achieve the above object, the present invention proposes a method for preparing a self-healing film capacitor, comprising the following steps: S1, substrate surface treatment, the polymer film substrate is ultrasonically cleaned with deionized water, anhydrous ethanol and surfactant solution in sequence to remove residual impurities on the surface, the substrate surface is treated with plasma of a mixed gas of oxygen and argon to enhance surface polarity and chemical activity, the treatment time is 60 to 90 seconds, and a silane coupling agent is sprayed on the treated film surface to form a functional layer that enhances adhesion; S2. Deposition of a conductive metal layer: depositing a conductive metal layer with a thickness of 10-50 nanometers on the surface of the substrate by magnetron sputtering or electron beam evaporation, wherein the conductive metal is aluminum, copper or silver, and monitoring the deposition rate and film thickness uniformity in real time during the deposition process to ensure that the surface roughness Ra value of the metal layer is less than 5 nanometers; S3, preparation of self-healing coating, preparing a coating liquid containing microcapsules, wherein the microcapsules use chitosan, polylactic acid or polyurethane as wall materials, and the core material includes a conductive material and a repair agent, and the coating liquid is evenly covered on the surface of the conductive metal layer by electrostatic spraying or dip coating. The particle size of the microcapsules is 1-3 microns, and the coating thickness is 1-10 microns; S4, coating curing and strengthening treatment, the coated film is cured at 80-150°C, initially at 80-100°C for 1-2 hours, then at 120-150°C for 0.5-1 hour, and a moisture-proof coating is sprayed on the coating surface, the coating material being a fluorinated polymer or a silicon-based material; S5, lamination and packaging, multiple layers of coated films are laminated, and an insulating layer made of polyimide or polyester film is arranged between the layers, and the thickness of the insulating layer is 1-5 microns. The laminated components are packaged by vacuum hot pressing. The packaging material is silicone rubber with added nanofillers. The packaging temperature is 80-120°C and the pressure is 0.1-0.5 MPa.

[0006] The preparation method of the self-healing thin film capacitor of the present invention, by introducing a microcapsule coating and an optimized preparation process, can quickly repair the conductive path after a local breakdown, thereby significantly improving the reliability and service life of the capacitor. This technical solution not only effectively solves the problem that traditional thin film capacitors cannot self-repair, but also exhibits excellent stability and anti-breakdown performance under a variety of environmental conditions.

[0007] In addition, the frying oven with rapid shaping and flipping functions according to the present invention may also have the following additional technical features: Specifically, the plasma gas volume ratio in the substrate surface treatment is 1:1, and the treatment time is 60 to 90 seconds to achieve optimal surface activity and polarity.

[0008] Specifically, the conductive metal layer deposition adopts a closed-loop control system to monitor the deposition rate and thickness in real time, the deposition rate is 0.8-1.5 nm / s, and the substrate temperature is 30-40°C.

[0009] Specifically, the conductive metal layer deposition adopts a closed-loop control system to monitor the deposition rate and thickness in real time, the deposition rate is 0.8-1.5 nm / s, and the substrate temperature is 30-40°C.

[0010] Specifically, the microcapsules are prepared by emulsion polymerization, with a particle size of 1-3 microns and a shell thickness of 50-200 nanometers, and the particle size uniformity is controlled by adjusting the emulsifier ratio and stirring rate.

[0011] Specifically, in the coating curing step, ultraviolet light curing treatment is added in the initial stage of curing to accelerate the cross-linking reaction of the coating and improve the curing efficiency and surface uniformity.

[0012] Specifically, the insulating layer material of the laminated assembly is high dielectric constant polyimide, the dielectric constant of which ranges from 3.5 to 5.0, and the lamination pressing temperature is 100 to 120°C.

[0013] Specifically, in the packaging step, the packaging material is silicone rubber with 5% to 10% silicon dioxide added by mass to improve the thermal conductivity and mechanical strength of the packaging.

[0014] Specifically, the time for the microcapsules of the self-healing coating to release the conductive material and the repair agent under the action of the electric field is less than 5 seconds, the recovery rate of the conductive path after release exceeds 90%, and the repair effect can be repeated more than 5 times without significant performance degradation.

[0015] Specifically, after the film capacitor operates for 5000 hours in an environment with a temperature range of -40°C to 85°C and a relative humidity of 30% to 90%, the change in capacitance value is less than 1%, and the local breakdown test verifies that its self-healing performance is better than that of traditional film capacitors.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 It is a schematic diagram of the preparation method of the self-healing film capacitor of the present invention. DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limitations of the present invention. On the contrary, embodiments of the present invention include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0019] The following describes a method for preparing a self-healing thin film capacitor according to an embodiment of the present invention in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, the method for preparing the self-healing thin film capacitor according to the embodiment of the present invention may include the following steps: S1. Surface treatment of the substrate: ultrasonically cleaning the polymer film substrate with deionized water, anhydrous ethanol and surfactant solution in sequence to remove residual impurities on the surface; treating the substrate surface with plasma of a mixed gas of oxygen and argon to enhance surface polarity and chemical activity; the treatment time is 60-90 seconds; spraying a silane coupling agent on the treated film surface to form a functional layer that enhances adhesion; S2. Deposition of a conductive metal layer: depositing a conductive metal layer with a thickness of 10-50 nanometers on the surface of the substrate by magnetron sputtering or electron beam evaporation, wherein the conductive metal is aluminum, copper or silver, and monitoring the deposition rate and film thickness uniformity in real time during the deposition process to ensure that the surface roughness Ra value of the metal layer is less than 5 nanometers; S3, preparation of self-healing coating, preparing a coating liquid containing microcapsules, wherein the microcapsules use chitosan, polylactic acid or polyurethane as wall materials, and the core material includes a conductive material and a repair agent, and the coating liquid is evenly covered on the surface of the conductive metal layer by electrostatic spraying or dip coating. The particle size of the microcapsules is 1-3 microns, and the coating thickness is 1-10 microns; S4, coating curing and strengthening treatment, the coated film is cured at 80-150°C, initially at 80-100°C for 1-2 hours, then at 120-150°C for 0.5-1 hour, and a moisture-proof coating is sprayed on the coating surface, the coating material being a fluorinated polymer or a silicon-based material; S5, lamination and packaging, multiple layers of coated films are laminated, and an insulating layer made of polyimide or polyester film is arranged between the layers, and the thickness of the insulating layer is 1-5 microns. The laminated components are packaged by vacuum hot pressing. The packaging material is silicone rubber with added nanofillers. The packaging temperature is 80-120°C and the pressure is 0.1-0.5 MPa.

[0021] It should be noted that, in the surface treatment process of the substrate described in this embodiment, ultrasonic cleaning with deionized water, anhydrous ethanol and surfactant solution is used to effectively remove surface impurities, and then oxygen and argon plasma are used to enhance the surface polarity and chemical activity to ensure good adhesion of the metal layer. The deposition of the conductive metal layer uses highly conductive materials such as aluminum, copper or silver. The deposition rate and film thickness uniformity are controlled by magnetron sputtering or electron beam evaporation, so that the surface roughness of the metal layer is less than 5 nanometers, ensuring the electrical performance of the capacitor. In the preparation process of the self-healing coating, a coating liquid containing microcapsules is prepared, wherein the wall material of the microcapsules is chitosan, polylactic acid Or polyurethane and other materials, the core material contains conductive materials and repair agents to ensure that the damaged area can be quickly repaired after local breakdown. The coating is evenly applied by electrostatic spraying or dipping, and is cured at 80-150°C to give the coating excellent repair performance and stability. Finally, through the lamination and packaging process, the multi-layer coating film is superimposed, and polyimide or polyester film is used as the insulating layer. It is packaged by vacuum hot pressing to ensure that the entire capacitor can maintain efficient self-repair capabilities under different working environments. The overall process flow is precisely optimized to improve the reliability and service life of the capacitor, and meet the needs of high-performance electronic devices for film capacitors.

[0022] Furthermore, the plasma gas volume ratio in the substrate surface treatment is 1:1, and the treatment time is 60-90 seconds to achieve optimal surface activity and polarity.

[0023] Furthermore, the conductive metal layer deposition adopts a closed-loop control system to monitor the deposition rate and thickness in real time, the deposition rate is 0.8-1.5 nm / s, and the substrate temperature is 30-40°C.

[0024] Furthermore, the conductive metal layer deposition adopts a closed-loop control system to monitor the deposition rate and thickness in real time, the deposition rate is 0.8-1.5 nm / s, and the substrate temperature is 30-40°C.

[0025] Furthermore, the microcapsules are prepared by emulsion polymerization, with a particle size of 1-3 microns and a shell thickness of 50-200 nanometers, and the particle size uniformity is controlled by adjusting the emulsifier ratio and stirring rate.

[0026] Furthermore, in the coating curing step, ultraviolet light curing treatment is added in the initial stage of curing to accelerate the cross-linking reaction of the coating and improve the curing efficiency and surface uniformity.

[0027] Furthermore, the insulating layer material of the laminated assembly is high dielectric constant polyimide, the dielectric constant of which is in the range of 3.5-5.0, and the lamination pressing temperature is 100-120°C.

[0028] Furthermore, in the packaging step, the packaging material is silicone rubber with 5% to 10% silica added by mass to improve the thermal conductivity and mechanical strength of the packaging.

[0029] Furthermore, the time for the microcapsules of the self-healing coating to release the conductive material and the repair agent under the action of the electric field is less than 5 seconds, the recovery rate of the conductive path after release is more than 90%, and the repair effect can be repeated more than 5 times without significant performance degradation.

[0030] Furthermore, after the film capacitor operates for 5000 hours in an environment with a temperature range of -40°C to 85°C and a relative humidity of 30% to 90%, the change in capacitance value is less than 1%, and the local breakdown test verifies that its self-healing performance is better than that of traditional film capacitors. Embodiment 1:

[0031] The preparation of a film capacitor with aluminum as a conductive metal layer, according to the contents of claim 1 and claim 2, selects a polyethylene terephthalate (PET) film with a thickness of 10 μm as a substrate, the substrate is washed with deionized water, anhydrous ethanol and a surfactant solution in sequence, and then surface treated with a plasma of a mixed gas of oxygen and argon (volume ratio 1:1), the plasma treatment enhances the polarity and activity of the substrate surface, thereby improving the adhesion of the subsequent metal layer and the coating, after the treatment, the film surface is sprayed with a silane coupling agent solution (concentration 5%), and the adhesion effect is further enhanced through the chemical bonding of the coupling agent molecules.

[0032] Conductive metal layer deposition, based on claim 1 and claim 3, uses magnetron sputtering to deposit an aluminum layer on the surface of the substrate. The excellent conductivity and lightweight characteristics of aluminum make it an ideal conductive metal material. The deposition process monitors the rate (1.2 nanometers / second) and thickness (30 nanometers) in real time to ensure the uniformity and low roughness of the metal layer surface (Ra value is 4.5 nanometers). The aluminum layer provides the basis for the conductive path and reduces the local electric field enhancement effect through a highly uniform surface morphology, reducing the risk of breakdown.

[0033] Preparation and coating of self-healing coating, according to claim 4 and claim 5, chitosan is selected as the wall material of microcapsules, and the core material is a mixture of graphene and epoxy resin. Chitosan has excellent mechanical stability, and graphene as a conductive filler can quickly restore conductivity. Microcapsules with a particle size of 2μm are prepared by emulsion polymerization and dispersed in a silicone-based coating liquid (microcapsule mass fraction is 20%). The electrostatic spraying method ensures uniform distribution of the coating, and the coating thickness is 5μm.

[0034] Coating curing and component packaging, according to the contents of claim 6 and claim 8, the coated film is cured at 90°C for 2 hours and then heated to 130°C for 1 hour, and a fluorinated polymer moisture-proof coating is sprayed on the surface. Subsequently, 5 layers of the coated film are stacked, and a polyimide insulating layer with a thickness of 3 μm is added between each layer. The film is packaged by vacuum hot pressing, and the packaging material is silicone rubber with 10% silica added. The packaging temperature is 100°C and the pressure is 0.3 MPa.

[0035] Specifically, when the capacitor partially breaks down, the electric field strength around the breakdown point increases sharply, causing the microcapsules to rupture under the action of the high field, releasing a mixture of graphene and epoxy resin. The graphene forms a conductive network, and the epoxy resin fills the damaged area and repairs the conductive path, thereby restoring the capacitance performance of the film. Embodiment 2:

[0036] Preparation of film capacitors with copper as the conductive metal layer, substrate treatment, according to the content of claim 1, a polyimide (PI) film with a thickness of 12μm is selected as the substrate, and a mixed gas plasma of oxygen and argon is used for 75 seconds, followed by spraying a silane coupling agent with a concentration of 7%, standing for 10 minutes and then drying. This process also enhances the bonding strength between the coating and the metal layer.

[0037] Conductive metal layer deposition, according to claim 3, a copper layer with a thickness of 40 nanometers is deposited by electron beam evaporation. Copper has better conductivity than aluminum and is suitable for scenarios with higher conductivity requirements. The deposition rate is 0.9 nanometers per second, the substrate temperature is controlled at 35°C, and the self-healing coating is prepared and coated based on claims 4 and 5, using polylactic acid as the microcapsule wall material, silver nanowires and UV-cured polymers as the core material. Microcapsules (particle size 3μm) are prepared by spray drying. Dip coating is used in the coating process, the coating thickness is 7μm, the coating is cured and the component is encapsulated, and the curing step is similar to Example 1, curing at 150°C for 0.5 hours, and spraying a silicon-based moisture-proof coating with a thickness of 2.5μm. The component is stacked with 6 layers, the insulating layer is a high dielectric constant polyimide material with a thickness of 4μm, and is encapsulated by hot pressing, the encapsulation temperature is 110°C, and the pressure is 0.4 MPa.

[0038] Specifically, when breakdown occurs, the local electric field causes the microcapsules to release silver nanowires and polymers. The silver nanowires form an efficient conductive path, while the polymer solidifies to repair the insulation of the breakdown area, ensuring that the film capacitor quickly recovers its function. Embodiment three:

[0039] Preparation of film capacitors with silver as the conductive metal layer, substrate treatment, according to the content of claim 2, select a polyester (PET) film with a thickness of 15μm, treat the surface with oxygen plasma, and spray a titanate coupling agent with a concentration of 3%, let it stand for 8 minutes and then dry it.

[0040] Conductive metal layer deposition, according to claim 1 and claim 3, a silver layer with a thickness of 20 nanometers is deposited by magnetron sputtering, the deposition rate is 1.5 nanometers / second, and the substrate temperature is 40°C. Self-healing coating preparation and coating, based on claim 4, polyurethane is selected as the microcapsule wall material, and the core material is a mixture of carbon nanotubes and epoxy resin. The microcapsule particle size is 1.5μm, and the electrostatic spraying forms a coating with a thickness of 4μm. The coating is cured and the component is encapsulated. The curing step is consistent with Example 1. The component is stacked with 8 layers, the insulating layer is a polyester film with a thickness of 3μm, and the hot pressing packaging temperature is 120°C and the pressure is 0.5 MPa.

[0041] Specifically, when a local breakdown occurs, the microcapsules release carbon nanotubes and epoxy resin. The carbon nanotubes form a conductive network, while the epoxy resin fills the damage, completing rapid repair.

[0042] In the description of this specification, 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 the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0044] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and deform the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a self-healing film capacitor, characterized in that: The following steps are involved: S1, substrate surface treatment, the polymer film substrate is ultrasonically cleaned with deionized water, anhydrous ethanol and surfactant solution in sequence to remove residual impurities on the surface, the substrate surface is treated with plasma of a mixed gas of oxygen and argon to enhance surface polarity and chemical activity, the treatment time is 60 to 90 seconds, and a silane coupling agent is sprayed on the treated film surface to form a functional layer that enhances adhesion; S2. Deposition of a conductive metal layer: depositing a conductive metal layer with a thickness of 10-50 nanometers on the surface of the substrate by magnetron sputtering or electron beam evaporation, wherein the conductive metal is aluminum, copper or silver, and monitoring the deposition rate and film thickness uniformity in real time during the deposition process to ensure that the surface roughness Ra value of the metal layer is less than 5 nanometers; S3, preparation of self-healing coating, preparing a coating liquid containing microcapsules, wherein the microcapsules use chitosan, polylactic acid or polyurethane as wall materials, and the core material includes a conductive material and a repair agent, and the coating liquid is evenly covered on the surface of the conductive metal layer by electrostatic spraying or dip coating. The particle size of the microcapsules is 1-3 microns, and the coating thickness is 1-10 microns; S4, coating curing and strengthening treatment, the coated film is cured at 80-150°C, initially at 80-100°C for 1-2 hours, then at 120-150°C for 0.5-1 hour, and a moisture-proof coating is sprayed on the coating surface, the coating material being a fluorinated polymer or a silicon-based material; S5, lamination and packaging, multiple layers of coated films are laminated, and an insulating layer made of polyimide or polyester film is arranged between the layers, and the thickness of the insulating layer is 1-5 microns. The laminated components are packaged by vacuum hot pressing. The packaging material is silicone rubber with added nanofillers. The packaging temperature is 80-120°C and the pressure is 0.1-0.5 MPa.

2. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: The plasma gas volume ratio in the substrate surface treatment is 1:1, and the treatment time is 60 to 90 seconds to achieve optimal surface activity and polarity.

3. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: The conductive metal layer deposition adopts a closed-loop control system to monitor the deposition rate and thickness in real time. The deposition rate is 0.8-1.5 nm / s and the substrate temperature is 30-40°C.

4. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: The conductive metal layer deposition adopts a closed-loop control system to monitor the deposition rate and thickness in real time. The deposition rate is 0.8-1.5 nm / s and the substrate temperature is 30-40°C.

5. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: The microcapsules are prepared by emulsion polymerization, with a particle size of 1-3 microns and a shell thickness of 50-200 nanometers. The particle size uniformity is controlled by adjusting the emulsifier ratio and stirring rate.

6. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: In the coating curing step, ultraviolet light curing treatment is added in the initial stage of curing to accelerate the cross-linking reaction of the coating and improve the curing efficiency and surface uniformity.

7. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: The insulating layer material of the laminated assembly is high dielectric constant polyimide, the dielectric constant of which ranges from 3.5 to 5.0, and the lamination pressing temperature is 100 to 120°C.

8. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: In the packaging step, the packaging material is silicone rubber with 5% to 10% silicon dioxide added by mass to improve the thermal conductivity and mechanical strength of the packaging.

9. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: The time for the microcapsules of the self-healing coating to release the conductive material and the repair agent under the action of the electric field is less than 5 seconds, and the recovery rate of the conductive path after release exceeds 90%. The repair effect can be repeated more than 5 times without significant performance degradation.

10. The method for preparing a self-healing thin film capacitor according to claim 1, characterized in that: After the film capacitor operates for 5000 hours in an environment with a temperature range of -40°C to 85°C and a relative humidity of 30% to 90%, the capacitance value changes by less than 1%, and a local breakdown test verifies that its self-healing performance is better than that of traditional film capacitors.

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