Crosslinked Dielectric Film Capacitor for High-Temperature Reliability
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Solution Overview
Problem
Film capacitors face challenges in maintaining long-term reliability in high temperature environments due to insufficient heat resistance, leading to potential degradation and reduced electrostatic capacitance.
Innovation Solution
The film capacitor and its dielectric resin film are designed with a crosslink density of 2700 mol/m³ or more at 225°C and a storage elastic modulus of 1.1 GPa or more at 125°C, incorporating a metal layer with a fuse portion, to enhance durability and maintain capacitance under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a dielectric resin film made of thermosetting resin is used to increase heat resistance, then the glass transition point can be raised to 130°C or higher, but the long-term reliability in high temperature environments of 125°C or higher remains insufficient
Solution Approach 1:
The patent changes the evaluation parameter from glass transition point to crosslink density at high temperature (2700 mol/m³ or more at 125°C). This parameter change reveals that the previous glass transition point metric was insufficient for predicting long-term high temperature reliability, and establishes crosslink density as the new critical parameter for ensuring capacitor life in high temperature environments.
Solution Approach 2:
The patent uses a composite resin composition containing both a thermoplastic resin component and a thermosetting resin component. The thermoplastic resin (such as polyether or polyester polyol) provides flexibility and processability, while the thermosetting resin (such as isocyanate compound or epoxy resin) provides high temperature stability and forms the crosslinked network structure that ensures long-term reliability at 125°C or higher.
2Stability of the object's composition
If the crosslink density is increased to improve high temperature stability, then the storage elastic modulus at 125°C can be maintained at 1.1 GPa or more, but the risk of brittle failure increases
Solution Approach 1:
The patent creates local quality differentiation within the resin film by controlling the crosslink density distribution and using a blend of thermoplastic and thermosetting resins. The thermosetting resin provides localized crosslinked regions for high temperature stability, while the thermoplastic resin maintains regions with sufficient flexibility to prevent brittle failure, achieving both high temperature stability and damage resistance.
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 design enables a long-life film capacitor capable of operating reliably in high temperature environments, suppressing capacitance loss and preventing brittle failure.
Implementation Method 1
the dielectric resin film has a crosslink density at 225°C of 2700 mol/m³ or more wherein n represents the crosslink density
Implementation Method 2
the dielectric resin film has a storage elastic modulus at 125°C of 1.1 GPa or more
Data Source
Figure 1~2
AI summary
A film capacitor of the present invention includes a dielectric resin film and a metal layer provided on one surface of the dielectric resin film. In a first aspect, the dielectric resin film has a crosslink density at 225°C of 2700 mol/m3 or more. In a second aspect, the dielectric resin film has a storage elastic modulus at 125°C of 1.1 GPa or more.