Solid Electrolytic Capacitor Anode Lead Extension Termination

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Solution Overview

Problem

The existing manufacturing methods for valve metal capacitors result in low volumetric efficiency due to the volume occupied by anode lead wires and thick cathode layers, which also compromise electrical performance and compatibility with industry standards.

Innovation Solution

The method involves forming an anode with a valve metal or conductive oxide, where the anode lead extension is exposed outside the encapsulant, allowing for a solid metal terminal attachment, and using solid metal current collectors that are thinner and more conductive than traditional metal-filled polymer layers, reducing the volume occupied by cathode layers and improving electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional manufacturing methods are used with anode lead wires and thick cathode layers, then electrical performance is maintained, but volumetric efficiency is reduced

Engineering Contradiction:
Improveelectrical performanceVSAvoidvolumetric efficiency
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent changes the physical state and properties of materials: replacing metal-filled polymer cathode layers with solid metal current collectors, and transitioning from anode lead wires to anode lead extensions. These parameter changes reduce volume while maintaining electrical performance through superior conductivity of solid metal materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures: combining valve metal anode with conductive oxide coatings, layering dielectric materials on the anode surface, and using solid metal current collectors with conductive adhesives. These composite structures optimize both electrical performance and volumetric efficiency through material property synergies.

Inventive Principle:
Principle #40Composite materials

2Reliability

If anode lead wires are used to connect anode to lead frame, then electrical connection is established, but device complexity and volume increase

Engineering Contradiction:
Improveelectrical connectionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the separate anode lead wire component, integrating its function directly into the anode structure through lead extensions. This removal of unnecessary components simplifies the overall device structure while maintaining electrical connectivity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the anode body and lead connection into a single integrated structure where the anode lead extension is a direct continuation of the anode. This consolidation eliminates the need for separate connection components and reduces structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If thick cathode layers are used for current collection, then electrical conductivity is sufficient, but volumetric efficiency decreases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidcathode layer volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent fundamentally changes the material parameter of cathode layers from metal-filled polymer composites to solid metal current collectors. This parameter change enables thinner layers with superior electrical conductivity, directly reducing cathode volume while improving or maintaining conductivity performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex, multi-layer cathode structures with simpler, thinner solid metal current collectors that achieve the same or better electrical performance with reduced material volume and simplified manufacturing.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 enhances volumetric efficiency by reducing the volume occupied by anode extensions and cathode layers, allowing for increased capacitance per unit volume while maintaining or improving electrical performance and conforming to industry standards.

Implementation Method 1

The valve metal anode body, 201, has an anode wire, 3, extending therefrom. The anode wire is electrically connected to an anode lead, 4, typically by welding. A dielectric, 5, on at least a portion of the anode separates the anode from a cathode, 6.

Methodology Applied
Scientific EffectAnodization: Anodising

Implementation Method 2

At least one solid metal current collector is adhered to the cathode layer with conductive adhesive.

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 3

The anode wire is electrically connected to an anode lead, 4, typically by welding.

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2517220B1Solid electrolytic capacitor and method of manufacture
Publication Date: 2018.05.16 KEMET ELECTRONICS CORP
  • EP2517220B1 patent drawingFigure 1A~1B
  • EP2517220B1 patent drawingFigure 2~3
  • EP2517220B1 patent drawingFigure 4~5

AI summary

An improved solid electrolytic capacitor and method of forming a solid electrolytic capacitor is described. The method includes forming an anode comprising a valve metal or conductive oxide of a valve metal wherein an anode lead extension protrudes from the anode. A dielectric is formed on the anode and a cathode layer is formed on the dielectric. The anode, dielectric, and cathode layer are encased in a non-conducting material and the anode lead extension is exposed outside of the encasement at a side surface. A conductive metal layer is adhered to the anode lead extension which allows termination preferably by electrically connecting a preformed solid metal terminal, most preferably an L shaped terminal, to the conductive metal layer at the side surface.