Solid Electrolytic Capacitor Projections for Adhesion

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Solution Overview

Problem

In electronic components, particularly solid electrolytic capacitors, the boundary between the conductive carbon layer and the semiconductor layer tends to separate easily under high temperature and high humidity, leading to increased equivalent series resistance (ESR) and leakage current over time.

Innovation Solution

The introduction of projections with a specific height range on the outer surface of the semiconductor layer, which are embedded into the conductive carbon layer to a depth of at least 25% of its thickness, enhances adhesiveness and prevents separation between the semiconductor and conductive carbon layers, even under prolonged exposure to high temperature and humidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a conductive carbon layer is laminated on a semiconductor layer, then electrical conductivity is improved, but the boundary between layers separates easily under thermal and mechanical stress

Engineering Contradiction:
Improveelectrical conductivityVSAvoidboundary adhesion
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by forming projections on the semiconductor layer surface before laminating the conductive carbon layer. These projections are created in advance through a molding process that shapes the semiconductor layer itself, providing a pre-configured anchoring structure that prevents subsequent separation under thermal and mechanical stress.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs spheroidality by creating dome-shaped or hemispherical projections on the semiconductor layer surface. These curved, rounded structures provide superior mechanical interlocking compared to flat surfaces, allowing the conductive carbon layer to conform to and adhere more effectively to the contours of the projections, thereby preventing delamination.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If the semiconductor layer surface is made flat, then manufacturing simplicity is maintained, but adhesion to the conductive carbon layer deteriorates under high temperature and humidity

Engineering Contradiction:
Improvesurface preparation simplicityVSAvoidlayer adhesion under stress
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the semiconductor layer surface into multiple discrete projection structures rather than maintaining a continuous flat surface. This segmentation creates numerous individual anchoring points that collectively provide superior adhesion while being formed through a single integrated molding process, thus maintaining manufacturing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by creating localized raised projections at specific positions on the semiconductor layer surface while keeping the bulk material properties uniform. This local structural modification provides enhanced adhesion precisely where the conductive carbon layer contacts the semiconductor layer, without affecting the overall manufacturing process or other functional areas.

Inventive Principle:
Principle #3Local quality

3Reliability

If projections are added to the semiconductor layer surface, then adhesion to the conductive carbon layer is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveboundary adhesionVSAvoidsurface structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies merging by combining the projection formation step with the semiconductor layer molding process itself. The projections are created as an integrated part of the layer formation through co-molding or over-molding techniques, eliminating the need for separate post-processing steps to create the surface features, thus reducing overall manufacturing complexity despite the enhanced surface structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements universality by designing the projection structure to serve multiple functions simultaneously: it provides mechanical interlocking for adhesion, increases surface area for better electrical contact, and can be formed through a single molding operation. This multi-functionality reduces the need for additional components or processes, offsetting the apparent complexity with operational efficiency.

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

Data Source

PatentEP2251880B1Element for electronic component
Publication Date: 2019.12.04 RESONAC HOLDINGS CORP
  • EP2251880B1 patent drawingFigure 1

AI summary

A surface of an anode body made of a metal material having a valve action is oxidized so as to form a dielectric layer, a conductive polymer precursor solution is stuck to the surface of the dielectric layer, the solvent is evaporated in an atmosphere of a relative humidity of 30 to 45 % to be removed, electropolymerization is carried out so as to obtain a semiconductor layer having projections being 2 to 70 µm high on the outer surface thereof, a conductive carbon layer is laminated using a conductive carbon paste, and a conductive metal layer containing a metal conductive powder and a binder is laminated so as to obtain an element for an electronic component, and the element for an electronic component is encapsulated by a resin so as to obtain an electronic component.