Multilayer Film Capacitor with Composite Conductive Insulating Stack
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polymer film capacitors have limitations in achieving high energy density and low dissipation, with typical energy densities not exceeding about 1 J/cc, necessitating an improvement in their design and materials to enhance their performance.
Innovation Solution
A capacitor design featuring a composite stack with thermoplastic conductive and insulating layers, where the conductive layers have a total thickness greater than three times that of the insulating layers, and include conductive particles above the percolation threshold, optimized through co-extrusion and stretching processes to achieve desired electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If polymer film capacitors use conventional dielectric material designs, then they achieve improved high-temperature characteristics and low dissipation factors, but they cannot achieve energy densities much higher than about 1 J/cc
Solution Approach 1:
The patent employs a composite dielectric structure consisting of multiple layers with different properties (high-k dielectric layers, low-loss dielectric layers, and conductive layers) to simultaneously achieve high energy density and low dissipation factors. The composite stack combines materials with complementary characteristics to resolve the contradiction between energy storage capacity and energy loss.
Solution Approach 2:
The dielectric material is divided into multiple functional layers including high-k dielectric layers for energy storage, low-loss dielectric layers for reducing dissipation, and conductive layers for charge collection. This segmentation allows each layer to optimize its specific function while working together to achieve both high energy density and low dissipation.
2Quantity of substance
If the capacitor uses a composite stack with thick conductive layers and thin insulating layers, then energy density increases to greater than 6 J/cc, but the manufacturing complexity increases
Solution Approach 1:
The patent combines multiple dielectric layers and conductive layers into a single integrated composite stack structure that is co-extruded as one piece. This merging of multiple functional layers into a unified structure achieves high energy density while simplifying the manufacturing process compared to assembling separate layers.
Solution Approach 2:
The patent optimizes the thickness parameters of conductive and insulating layers, establishing that conductive layers should have a total thickness greater than three times that of insulating layers. This parameter optimization achieves maximum energy density while maintaining manufacturability through co-extrusion processes.
3Volume of stationary object
If conductive particles are added above the percolation threshold, then the effective dielectric function increases at low frequencies, but the loss tangent may increase
Solution Approach 1:
The patent introduces conductive particles locally within specific dielectric layers to enhance the effective dielectric function at low frequencies. By strategically placing conductive particles in high-k dielectric layers rather than uniformly distributing them, the patent achieves increased dielectric function while controlling the loss tangent through localized modification of material properties.
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 achieves high low-frequency effective dielectric function, high resonance frequency, and low loss tangent, resulting in improved energy density, dielectric breakdown strength, and reduced defects, enabling energy densities greater than 6 J/cc and effective dielectric properties across a wide frequency range.
Implementation Method 1
At least one of the two or more thermoplastic conductive layers includes a thermoplastic polymer blended with a plurality of conductive particles at a concentration higher than a percolation threshold
Implementation Method 2
Methods consistent with the present description include co-extrusion of materials to form at least portions of the capacitor
Data Source
AI summary
A multilayer film capacitor having a composite stack disposed between two electrodes where the composite stack includes at least one thermoplastic conductive layer and at least one thermoplastic insulating layer. The total thickness of the conductive layers is at least 3 times the total thickness of the insulating layers. The conductive layers may include a thermoplastic polymer blended with conductive particles at a concentration higher than a percolation threshold.