Polymer-Ceramic Composite Capacitor TCC Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional dielectric composite capacitor materials exhibit significant changes in capacitance due to temperature variations, making them unsuitable for applications requiring stability over a wide temperature range, and they often have poor mechanical and processing properties.

Innovation Solution

A polymer-ceramic composite material is developed, comprising a blend of an epoxy-containing polymer and ferroelectric ceramic particles, which maintains a temperature coefficient of capacitance within ±5% over the range of −55° C. to 125° C., while offering excellent mechanical and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high loading of ceramic filler materials is added to increase capacitance density, then capacitance density is improved, but mechanical properties and processing properties deteriorate significantly

Engineering Contradiction:

Improvecapacitance densityVSAvoidmechanical properties

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of polymer matrix (epoxy resin) and ceramic filler particles (barium titanate, strontium titanate, or lead zirconate titanate). This composite structure allows the material to exhibit both high capacitance density from the ceramic phase and good mechanical properties from the polymer matrix, resolving the contradiction between capacitance enhancement and mechanical strength maintenance.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If high loading of ceramic filler materials is added to increase capacitance density, then capacitance density is improved, but brittleness increases and processing becomes difficult

Engineering Contradiction:

Improvecapacitance densityVSAvoidprocessing properties

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The polymer-ceramic composite structure provides a matrix that binds ceramic particles while maintaining processability. The polymer component allows for conventional processing techniques such as molding and lamination, making the high-capacitance material easy to manufacture despite the high ceramic loading.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If materials with high dielectric constants are used to increase capacitance, then capacitance density is improved, but temperature coefficient of capacitance increases

Engineering Contradiction:

Improvecapacitance densityVSAvoidtemperature coefficient of capacitance

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent carefully controls the composition parameters of the composite, including the ratio of polymer to ceramic (typically 20-80 wt% ceramic), particle size distribution (0.1-10 micrometers), and dielectric constant of the polymer matrix (3-10). By optimizing these parameters, the composite achieves high capacitance density while maintaining a low temperature coefficient of capacitance (±10% or better over -55°C to +125°C).

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The composite structure combines materials with complementary temperature-stability characteristics. The polymer matrix provides thermal stability that compensates for the temperature sensitivity of the ceramic filler, resulting in a composite with superior temperature coefficient performance compared to the individual components.

Inventive Principle:

Principle #40Composite materials

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 composite material achieves stable capacitance across a broad temperature range, with minimal change in temperature coefficient of capacitance, along with improved mechanical strength and ease of processing, making it suitable for high-performance capacitors and printed circuit boards.

Implementation Method 1

a polymer-ceramic composite material which comprises a blend of a polymer component and ferroelectric ceramic particles

Methodology Applied

Scientific EffectFerroelectricity:

Implementation Method 2

The capacitance depends primarily on the shape and size of the capacitor layers and the dielectric constant of the insulating material

Methodology Applied

Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 3

which polymer component comprises at least one epoxy containing polymer, in an amount of from about 5 wt. % to about 95 wt. % based on the weight of the polymer component, and at least one polymer having a plurality of epoxy-reactive groups

Methodology Applied

Scientific EffectEpoxy reaction: Chemical Bonding

Data Source

PatentUS7672113B2Polymer-ceramic composites with excellent TCC

Publication Date: 2010.03.02 MITSUI MINING & SMELTING CO LTD

AI summary

Polymer-ceramic composite materials for use in the formation of capacitors, which materials exhibit very low changes in temperature coefficient of capacitance (TCC) in response to changes in temperature within the range of from about −55° C. to about 125° C. Specifically, these capacitor materials have a change in TCC ranging from about −5% to about +5%, in response to changes in temperature within the desired temperature range. The inventive composite materials comprise a blend of a polymer component and ferroelectric ceramic particles, wherein the polymer component includes at least one epoxy-containing polymer, and at least one polymer having epoxy-reactive groups. The inventive polymer-ceramic composite materials have excellent mechanical properties such as improved peel strength and lack of brittleness, electrical properties such as high dielectric constant, and improved processing characteristics.