Dual-Polymer Electrolytic Capacitor Structure for Low ESR

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Solution Overview

Problem

Existing electrolytic capacitors face challenges in reducing Equivalent Series Resistance (ESR) due to issues such as short circuits and increased resistance caused by insulation breakdown and deterioration of conductive polymer layers.

Innovation Solution

The electrolytic capacitor design incorporates a first solid electrolyte layer with a polythiophene polymer having a conductivity of less than or equal to 2 S/cm, followed by a second layer of polypyrrole polymer formed through electrolytic polymerization, which reduces ESR by enhancing insulation and maintaining low resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single solid electrolyte layer containing conductive polymer is used, then the capacitor structure is simple, but the ESR is high and insulation is insufficient

Engineering Contradiction:

Improveinsulation performanceVSAvoidelectrolyte layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The solid electrolyte layer is divided into two distinct layers: a first solid electrolyte layer containing polythiophene-based conductive polymer and a second solid electrolyte layer containing polypyrrole-based conductive polymer. This segmentation allows each layer to perform specialized functions - the first layer provides insulation and thermal stability, while the second layer provides conductivity, thereby resolving the contradiction between insulation performance and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure with two different conductive polymers (polythiophene and polypyrrole) having complementary properties. The polythiophene layer contributes thermal stability and insulation, while the polypyrrole layer contributes high conductivity. This composite approach achieves both good insulation performance and low ESR without requiring overly complex structures.

Inventive Principle:

Principle #40Composite materials

2Reliability

If high conductivity polymer is used to reduce ESR, then ESR decreases, but insulation breakdown and deterioration occur more easily

Engineering Contradiction:

Improveresistance stabilityVSAvoidESR

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

Different regions of the solid electrolyte are assigned different properties: the first layer (polythiophene) has lower conductivity but high thermal stability and insulation, while the second layer (polypyrrole) has high conductivity for low ESR. This local differentiation allows the system to achieve low overall ESR while maintaining insulation stability, preventing the contradiction between reducing ESR and preventing insulation breakdown.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If polythiophene layer conductivity is increased to improve electron transport, then conductivity improves, but insulation performance deteriorates

Engineering Contradiction:

Improveelectron transport efficiencyVSAvoidinsulation performance

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

Instead of making the polythiophene layer highly conductive, the invention inverts the approach by keeping it with moderate conductivity (≤2 S/cm) and using it primarily for insulation and thermal stability. The high conductivity function is inverted to the polypyrrole layer, which is specifically positioned to handle electron transport. This inversion resolves the contradiction by assigning functions based on material strengths rather than maximizing conductivity in the polythiophene layer.

Inventive Principle:

Principle #13The other way round (Inversion)

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

This configuration effectively minimizes ESR and leakage current while maintaining high capacitance, with the polythiophene layer's thermal stability and energy level difference contributing to reduced resistance increases.

Implementation Method 1

a first solid electrolyte layer covering the dielectric layer and containing a first conductive polymer whose basic skeleton is polythiophene; a conductivity of the first solid electrolyte layer is less than or equal to 2 S/cm

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

a third step of forming a second solid electrolyte layer containing a second conductive polymer by performing electrolytic polymerization of a precursor of the second conductive polymer on the first solid electrolyte layer, the second conductive polymer including polypyrrole as a basic skeleton

Methodology Applied

Scientific EffectElectrolytic polymerization: Electrolysis

Implementation Method 3

The solid electrolyte layer contains a conductive polymer, and as the conductive polymer, for example, polypyrrole is used

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12462986B2Electrolytic capacitor and method for producing same

Publication Date: 2025.11.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An electrolytic capacitor includes an anode body, a dielectric layer covering the anode body, a first solid electrolyte layer covering the dielectric layer, and a second solid electrolyte layer covering the first solid electrolyte layer. The first solid electrolyte layer contains a first conductive polymer including polythiophene as a basic skeleton. The second solid electrolyte layer contains a second conductive polymer including polypyrrole as a basic skeleton. A conductivity of the first solid electrolyte layer is less than or equal to 2 S/cm.