Conductive Polymer Solution for Low ESR Capacitors

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Solution Overview

Problem

Conventional capacitor production methods require multiple steps and different treatment solutions for forming conductive polymer layers, making them time-consuming and complex, while also struggling to achieve low equivalent series resistance (ESR) and high capacitance.

Innovation Solution

A conductive polymer solution comprising a pi-conjugated conductive polymer, a polyanion, and a compound formed by reacting an oxirane or oxetane group with an anion, which is used to form a solid electrolyte layer without the need for separate inside and outside conductive polymer layer formations, allowing for a single-step process that adjusts the pH to a range of 2.0-6.0.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple treatment solutions and steps are used to form conductive polymer layers, then long-term reliability is improved, but manufacturing complexity and time increase

Engineering Contradiction:
Improvelong-term reliabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the formation of inside and outside conductive polymer layers into a single treatment step using one polymerization solution. The solution contains both water-soluble polymer and colloidal silica, enabling simultaneous formation of both layers with different properties through a unified process, thereby reducing manufacturing complexity while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The polymerization solution serves multiple functions: it forms the inside conductive polymer layer, forms the outside protective layer, provides adhesion between layers, and controls pH. This multi-functionality eliminates the need for separate treatment solutions and steps, reducing process complexity while ensuring reliable capacitor performance

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple treatment solutions and steps are used to form conductive polymer layers, then layer quality is improved, but productivity decreases

Engineering Contradiction:
Improveconductive polymer layer qualityVSAvoidcapacitor production efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent enables continuous formation of both inside and outside conductive polymer layers in a single uninterrupted polymerization step. The reaction proceeds continuously without intermediate drying or re-wetting steps, maintaining layer quality while significantly improving production efficiency and throughput

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

By merging the formation processes of inside and outside layers into one simultaneous operation, the patent eliminates sequential processing steps, reducing total manufacturing time and increasing productivity while maintaining the quality requirements for both layers

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If strong acid is used in conductive polymer solution, then polymerization is improved, but anode damage occurs

Engineering Contradiction:
Improvepolymerization efficiencyVSAvoidanode damage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces colloidal silica as an intermediary substance that mediates between the acidic polymerization environment and the anode. The silica particles form a protective colloidal structure that allows polymerization to proceed while preventing direct contact between strong acid and the anode surface, thus preventing damage

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state and distribution of acid in the solution by incorporating it into a colloidal system with silica. This transforms the acid from a free strong acid that damages the anode into a controlled component within the colloidal structure, maintaining polymerization efficiency while reducing harmful effects on the anode

Inventive Principle:
Principle #35Parameter changes

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 approach enables the production of capacitors with low ESR and high capacitance while maintaining long-term reliability, simplifying the production process and eliminating the need for multiple treatment solutions.

Implementation Method 1

a pi-conjugated conductive polymer, a polyanion with which the pi-conjugated conductive polymer is doped

Methodology Applied
Scientific EffectDoping: Dopants

Implementation Method 2

a conductive film containing a pi-conjugated conductive polymer may be used as the solid electrolyte layer

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a compound formed by reacting an oxirane or oxetane group with an anion

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3349228B1Electroconductive-polymer solution, capacitor, and process for producing capacitor
Publication Date: 2022.03.09 SHIN ETSU POLYMER CO LTD

AI summary

[Object] To provide a conductive polymer solution capable of forming a capacitor having a large capacitance, low ESR, and excellent long-term reliability without using treatment solutions for conductive polymer layer formation differing in composition, and without forming an inside conductive polymer layer by different approaches, the capacitor and a method for producing the capacitor [Solution] The present invention relates to: a conductive polymer solution which comprises a conductive polymer and a solvent, wherein the conductive polymer comprises a pi-conjugated conductive polymer, a polyanion with which the pi-conjugated conductive polymer has been doped, and a compound formed by reacting an oxirane or oxetane group with an anion making no contribution to the dope in the polyanion, and the solution has a pH in the range of 2.0 to 6.0; a capacitor which includes either the conductive polymer solution or the compounds remaining after removal of the solvent from the solution; and a method for producing a capacitor, comprising impregnating the capacitor with the conductive polymer solution and removing the solvent therefrom.