Dielectric Film Composition for Compact Film Capacitors
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Solution Overview
Problem
Film capacitors with dielectric films made of polypropylene resin have size limitations, hindering low-profile designs and high packaging density due to their large size compared to other electronic components, and existing solutions have not adequately addressed the need for smaller, high-performance alternatives.
Innovation Solution
A dielectric film comprising organic resin polymers, such as polyarylate and cycloolefin polymers, with added phenol, sulfur, or phosphorus monomers that enhance breakdown field strength, allowing for thinner films and reduced size while maintaining or improving insulation and oxidative stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polypropylene resin is used as the dielectric film material, then the film capacitor can prevent ignition and electric shock through self-restoration capability, but the film capacitor size becomes large, hindering low-profile design and high packaging density
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric film by incorporating aromatic polyesters (10-50 mass%) and cycloolefin polymers (50-90 mass%) instead of conventional polypropylene resin. This parameter change achieves both high breakdown voltage (≥20 kV/mm) and reduced film thickness (5 μm or less), resolving the contradiction between reliability and size.
Solution Approach 2:
The patent creates a composite dielectric film material combining aromatic polyester and cycloolefin polymer in specific ratios. This composite material achieves synergistic effects: aromatic polyester provides high breakdown voltage and self-restoration capability, while cycloolefin polymer enables thin-film formation and small size, thus resolving the contradiction between reliability and compactness.
2Volume of moving object
If the dielectric film thickness is reduced to decrease capacitor size, then packaging density increases, but the breakdown field strength and insulation performance may deteriorate
Solution Approach 1:
The patent changes the material parameters by selecting aromatic polyester and cycloolefin polymer with inherently high dielectric strength. This enables the film to achieve breakdown field strength ≥20 kV/mm even at thicknesses of 5 μm or less, resolving the contradiction between size reduction and insulation performance.
Solution Approach 2:
The patent optimizes the local molecular structure of the dielectric film through specific polymer selection and composition control. The aromatic polyester provides localized high breakdown strength regions, while the cycloolefin polymer ensures uniform thin-film formation, achieving both thinness and high insulation performance simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The enhanced breakdown field strength enables the use of thinner dielectric films, reducing the size of film capacitors and increasing their capacity, while also improving their durability and lifespan under high temperature conditions.
Implementation Method 1
a dielectric film according to an embodiment of the invention contains an organic resin polymer, and an organic resin monomer... the dielectric film having a breakdown field strength of 20 kV/mm or more
Implementation Method 2
a film capacitor is constructed of a dielectric film of polypropylene resin in film-like form having a vapor-deposited metallic membrane on its surface as an electrode
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
A dielectric film includes an organic resin polymer, and an organic resin monomer. The organic resin polymer includes at least one of polyarylate and cycloolefin polymer, the organic resin monomer includes at least one of phenol monomer, sulfur monomer, and phosphorus monomer, and a total content of the organic resin monomer falls in a range of 0.01 to 7.6 parts by mass based on of 100 parts by mass the organic resin polymer.