Solid Electrolytic Capacitor Anode Contact Roughness for Stronger Bonding

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Solution Overview

Problem

Existing solid electrolytic capacitors face issues with low bonding strength between conductive layers due to the anchor effect, leading to defects like peeling off, which deteriorate electrical and mechanical characteristics.

Innovation Solution

A solid electrolytic capacitor design featuring a contact layer with predetermined surface roughness on the anode terminal portion, formed using a metal material with lower ionization tendency than the anode body, and coated with an anode-side electrode layer to enhance bonding strength and electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a smooth surface is used between conductive layers, then the manufacturing process is simpler, but the bonding strength is insufficient leading to peeling defects

Engineering Contradiction:

Improvebonding strengthVSAvoidstructure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies a rough surface treatment to create an anchor effect between conductive layers. The irregular surface topology increases the contact area and mechanical interlocking between layers, preventing peeling defects while maintaining manufacturing feasibility through standard surface treatment processes.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The rough surface creates curved and irregular contact interfaces between conductive layers rather than flat surfaces. This curvature increases the effective bonding area and creates mechanical interlocking, enhancing adhesion strength without requiring complex manufacturing steps.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Strength

If the contact area between conductive layers is increased, then the bonding strength improves, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvebonding strengthVSAvoidsurface roughness control

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent specifies a controlled surface roughness parameter (Ra: 0.5 μm to 5 μm) to optimize the anchor effect. This parameter control ensures sufficient bonding strength while maintaining manufacturing feasibility, balancing the trade-off between bonding performance and manufacturing precision requirements.

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

The increased contact area and bonding strength between the contact layer and electrode layer result in improved electrical characteristics and mechanical reliability, reducing resistance and enhancing the capacitor's performance.

Implementation Method 1

a contact layer which is on an anode terminal portion, which is an end portion of the anode body, and has a surface with a predetermined surface roughness; and an anode-side electrode layer which covers the surface

Methodology Applied

Scientific EffectMechanical interlocking:

Data Source

PatentUS11742150B2Solid electrolytic capacitor including an exterior body that covers a capacitor element and method of manufacturing the same

Publication Date: 2023.08.29 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A capacitor element that has an anode body, a dielectric oxide film layer covering the anode body, and a cathode body formed on the dielectric oxide film layer; an exterior body that covers the capacitor element; a contact layer that is on an anode terminal, which is an end portion of the anode body, and has a surface with a predetermined surface roughness; and an anode-side electrode layer that covers the surface are provided.