Solid Electrolytic Capacitor Outer Electrode Layer ESR Reduction

Solution Overview

Problem

Solid electrolytic capacitors face high Equivalent Series Resistance (ESR) due to smooth outer electrode surfaces and material differences between the outer electrode and cathode layers, leading to cracking and increased contact resistance.

Innovation Solution

A solid electrolytic capacitor design featuring a porous sintered body with a dielectric layer, a solid electrolyte layer comprising an inner and outer electrode layer, where the outer electrode layer includes a solid particle containing layer with conductive polymer and solid particles, providing an irregular surface for enhanced bonding with the cathode layer, and the solid particles and base layer are made of the same material, such as graphite, to reduce ESR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a smooth outer electrode layer is formed by applying conductive polymer dispersion material, then the manufacturing process is simplified, but cracking occurs between the solid electrolyte layer and cathode layer

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidcracking resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a porous layer between the solid electrolyte layer and cathode layer. This porous structure absorbs thermal stress and prevents cracking while maintaining manufacturing simplicity. The porous material acts as a buffer zone that accommodates expansion and contraction during operation.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent uses composite materials for the outer electrode layer, combining conductive polymer with other materials that provide both smooth surface properties for easy manufacturing and cracking resistance. This composite approach allows simultaneous achievement of manufacturing simplicity and reliability.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If different materials are used for outer electrode layer and cathode layer, then functional requirements are met, but large contact resistance is generated

Engineering Contradiction:

Improvefunctional requirements satisfactionVSAvoidcontact resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediate layer between the outer electrode layer and cathode layer. This intermediate layer serves as a mediator that reduces contact resistance between dissimilar materials while allowing each layer to maintain its functional properties. The intermediate material is selected to have compatible properties with both adjacent layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses materials with gradually changing properties across the interface between outer electrode layer and cathode layer. This gradient homogeneity reduces abrupt material property changes, minimizing contact resistance while preserving functional requirements of each layer.

Inventive Principle:

Principle #33Homogeneity

3Ease of manufacture

If a smooth outer electrode surface is formed, then manufacturing is easier, but the contact area with cathode layer is reduced

Engineering Contradiction:

Improvesurface formation easeVSAvoidcontact area

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent introduces a porous layer between the solid electrolyte layer and cathode layer. This porous structure absorbs thermal stress and prevents cracking while maintaining manufacturing simplicity. The porous material acts as a buffer zone that accommodates expansion and contraction during operation.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent uses composite materials for the outer electrode layer, combining conductive polymer with other materials that provide both smooth surface properties for easy manufacturing and cracking resistance. This composite approach allows simultaneous achievement of manufacturing simplicity and reliability.

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 irregular surface of the outer electrode layer prevents cracking and increases the contact area, significantly reducing the ESR of the solid electrolytic capacitor, while the same material composition enhances bonding strength and manufacturing efficiency.

Implementation Method 1

a dispersion material liquid containing the conductive polymer dispersion material, the solid particles and a solvent is applied to the inner electrode layer

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

applying a dispersion material liquid containing the conductive polymer dispersion material, the solid particles and a solvent to the inner electrode layer, and then removing the solvent

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS9378896B2Solid electrolytic capacitor and method for manufacturing the same

Publication Date: 2016.06.28 KYOCERA AVX COMPONENTS (BANGKOK) LTD

AI summary

A solid electrolytic capacitor includes a porous sintered body made of a valve metal, a dielectric layer on the porous sintered body, a solid electrolyte layer on the dielectric layer, and a cathode layer on the solid electrolyte layer. The solid electrolyte layer includes an inner electrode layer covering the dielectric layer inside the porous sintered body and an outer electrode layer covering the inner electrode layer outside the porous sintered body. The outer electrode layer includes a solid particle containing layer formed by applying a dispersion material liquid containing a conductive polymer dispersion material, solid particles and a solvent to the inner electrode layer and then removing the solvent.