Multilayer Polymer Dielectric Film Charge Delocalization
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Solution Overview
Problem
Conventional polymer dielectric films used in capacitors lack sufficient energy storage capacity and breakdown strength, limiting their performance in high-energy applications.
Innovation Solution
A multilayer polymer dielectric film is developed, comprising alternating layers of polymers with varying permittivity and breakdown strength, fabricated using solventless coextrusion techniques, which maximizes energy density and breakdown strength by delocalizing charge build-up and optimizing layer thickness and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional single-layer polymer dielectric films are used, then the structure is simple and easy to manufacture, but the energy storage capacity and breakdown strength are insufficient
Solution Approach 1:
The dielectric film is divided into multiple thin layers (typically 5-500 nm each) with alternating high-permittivity and low-permittivity polymers. This segmentation allows charge delocalization at interfaces, preventing charge accumulation and significantly enhancing breakdown strength while maintaining manufacturability through coextrusion processes
Solution Approach 2:
The invention uses composite multilayer structures combining different polymer materials with complementary properties - high-permittivity polymers (e.g., PVDF, P(VDF-HFP)) for energy storage and low-permittivity polymers (e.g., PP, PET) for breakdown resistance. The synergistic combination achieves superior performance beyond what single materials can provide
2Use of energy by moving object
If high-permittivity polymer materials are used to increase energy density, then the energy storage capacity improves, but the breakdown strength decreases
Solution Approach 1:
Different regions of the multilayer film have specialized functions: high-permittivity layers are optimized for energy storage in regions where high electric field tolerance is needed, while low-permittivity layers provide breakdown resistance in regions where charge accumulation is likely. This local optimization allows the system to achieve high energy density without sacrificing breakdown strength
Solution Approach 2:
The low-permittivity polymer layers act as intermediary barriers between high-permittivity layers, preventing direct charge accumulation at interfaces. These intermediary layers delocalize charge build-up and protect the high-permittivity material from electrical breakdown, enabling the system to utilize the high energy storage capacity of the high-permittivity material without suffering from its inherent low breakdown strength
3Strength
If multilayer coextrusion techniques are used to fabricate the film, then the dielectric strength and energy density are enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
Multiple polymer layers are combined in a single coextrusion process, where molten polymers are extruded simultaneously through a multi-layer die to form the multilayer structure in one continuous operation. This merging of multiple materials and functions into a single manufacturing step enhances dielectric strength while avoiding the complexity of sequential layering processes
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 multilayer film significantly enhances energy storage capacity and breakdown strength, exceeding those of component materials, making it suitable for high-energy applications with improved reliability and efficiency.
Implementation Method 1
The first layer and second layer define an interface that delocalizes charge build-up in the layers
Data Source
AI summary
A multilayer polymer dielectric film includes a coextruded first dielectric layer and second dielectric layer. The first dielectric includes a first polymer material and the second dielectric layer includes a second polymer material. The first dielectric layer and the second dielectric layer defining an interface between the layers that delocalizes charges in the layers.