Oxide-Coated Capacitor Lead Wire for Moisture-Stable Insulation

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Solution Overview

Problem

Existing solid electrolytic capacitors face challenges with insulating rings that are expensive and ineffective in high moisture and temperature environments.

Innovation Solution

A solid electrolytic capacitor design featuring a lead wire with a core that extends outwardly from the capacitor element, coated with an oxide layer, and a method for forming this oxide layer through anodic oxidation after removing conductive material from the lead wire.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulating rings are used to protect the lead wire, then the lead wire is protected from moisture, but the cost increases and effectiveness is reduced in high moisture and temperature environments

Engineering Contradiction:
Improveprotection effectivenessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the insulating ring component entirely and replaces it with an oxide layer formed directly on the lead wire surface through anodic oxidation. This extraction of the separate insulating component simplifies the overall structure while maintaining protection functionality through the integrated oxide coating.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The oxide layer acts as an intermediary substance that provides both electrical insulation and moisture protection simultaneously. This intermediary layer eliminates the need for separate insulating rings while addressing the limitations of existing protection methods in high humidity and temperature conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conductive polymer is removed from the lead wire, then leakage current is reduced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveleakage currentVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent performs preliminary removal of conductive polymer from the lead wire surface before final assembly, and applies an oxide layer in advance to prevent future leakage issues. This preliminary action ensures low leakage current while the integrated process design minimizes manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The anodic oxidation process creates a self-forming protective oxide layer on the lead wire that automatically provides electrical insulation and moisture protection. This self-service mechanism eliminates the need for additional insulating components and simplifies the manufacturing process despite the extra oxidation step.

Inventive Principle:
Principle #25Self-service

3Reliability

If an oxide layer is formed on the lead wire through anodic oxidation, then electrical properties are improved, but additional manufacturing steps are required

Engineering Contradiction:
Improveelectrical propertiesVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines multiple functions into the single oxide layer formation step: electrical insulation, moisture protection, and corrosion resistance are all achieved simultaneously through the anodic oxidation process. This merging of functions improves electrical properties while minimizing the impact on manufacturing efficiency by consolidating protection requirements into one process step.

Inventive Principle:
Principle #5Merging (Combining)

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 capacitor exhibits improved electrical properties, including reduced leakage current and equivalent series resistance, and maintains performance in high humidity and temperature conditions.

Implementation Method 1

a method for forming this oxide layer through anodic oxidation after removing conductive material from the lead wire

Methodology Applied
Scientific EffectAnodic oxidation: Anodising

Data Source

PatentEP3542381B1Lead wire configuration for a solid electrolytic capacitor
Publication Date: 2025.05.14 KYOCERA AVX COMPONENTS CORP
  • EP3542381B1 patent drawingFigure 1
  • EP3542381B1 patent drawingFigure 2a~3b
  • EP3542381B1 patent drawingFigure 4a~4b

AI summary

A solid electrolytic capacitor that comprises a capacitor element, a lead wire, an anode termination, and a cathode termination is provided. The capacitor element contains a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric. Further, the lead wire is in electrical contact with the anode body and contains a first region that is located in proximity to a surface of the capacitor element. The lead wire contains a core that extends outwardly from the surface, and an oxide layer coats at least a portion of the core within the first region.