Electrode Foil Interface Layer for Capacitor Leak Current Suppression

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Solution Overview

Problem

Electrolytic capacitors with conductive polymer compound-covered dielectric layers experience increased leak current due to damage to the dielectric layer.

Innovation Solution

Incorporating an interface layer between the metal skeleton and dielectric layer of the electrode foil, composed of sulfur, nitrogen, or phosphorus, which forms an amorphous film to reduce leak current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a dielectric layer is formed by a gas phase method on a porous anode body, then the manufacturing process is simplified, but the dielectric layer surface becomes vulnerable to damage that increases leak current

Engineering Contradiction:

Improvedielectric layer formation processVSAvoidleak current

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

An interface layer comprising sulfur, nitrogen, or phosphorus is introduced as an intermediary between the metal skeleton and the dielectric layer. This interface layer acts as a protective mediator that prevents direct contact and potential damage between the dielectric layer and the conductive polymer compound, thereby suppressing leak current while maintaining the simplified gas phase formation process

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure consisting of the metal skeleton, the interface layer with specific elements (sulfur, nitrogen, or phosphorus), and the dielectric layer. This composite material structure enhances the overall reliability by combining the protective properties of the interface layer with the insulating properties of the dielectric layer, preventing damage-induced leak current increases

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 interface layer effectively suppresses leak current, enhancing the reliability of electrolytic capacitors, particularly in middle to high voltage types, by restoring dielectric layer damage and maintaining low crystallinity.

Implementation Method 1

an interface layer including a first element is present between the metal skeleton and the dielectric layer, and the first element is at least one selected from the group consisting of sulfur, nitrogen, and phosphorus

Methodology Applied

Scientific EffectAmorphous film formation:

Data Source

PatentUS20250379002A1Electrode foil for electrolytic capacitors, electrolytic capacitor, method for producing electrode foil for electrolytic capacitors, and method for producing electrolytic capacitor

Publication Date: 2025.12.11 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An electrode foil for an electrolytic capacitor includes an anode body having a porous portion and a core part continuous with the porous portion, a dielectric layer covering a surface of a metal skeleton forming the porous portion, wherein an interface layer including a first element is present between the metal skeleton and the dielectric layer, and the first element is at least one selected from the group consisting of sulfur, nitrogen, and phosphorus.