Solid Electrolytic Capacitor ESL Reduction via Composite Terminal Layer

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Solution Overview

Problem

Solid electrolytic capacitors face challenges in reducing equivalent series inductance (ESL) without deteriorating capacitor characteristics, especially when increasing the number of mounting terminals, which complicates production and mass production.

Innovation Solution

A solid electrolytic capacitor design featuring a device portion with a valve metal anode member, dielectric layer, insulator layer, and conductor layers, where a composite layer with insulating resin layers and hole portions is used to electrically connect the terminals, reducing ESL without the need for through holes and simplifying the production process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of mounting terminals is increased to reduce ESL, then the loop inductance decreases, but the production complexity increases and mass production becomes difficult

Engineering Contradiction:

ImproveESLVSAvoidproduction complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The capacitor is divided into multiple terminal sections with positive and negative terminals arranged alternately. Each terminal has its own conductor extending to the electrode portions, allowing independent connection without requiring through-holes. This segmentation enables reduced ESL through multiple parallel current paths while simplifying production by eliminating complex through-hole arrangements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a conventional single-plane terminal arrangement to a three-dimensional structure where terminals are arranged in alternate positive-negative sequences on the surface. Conductors extend vertically from the electrode portions to the mounting terminals, creating multiple spatial dimensions for current flow paths. This dimensional change reduces loop inductance while maintaining production simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If through holes are used to arrange conductors for multi-terminal configuration, then ESL is reduced, but capacitor characteristics deteriorate and mass production becomes difficult

Engineering Contradiction:

ImproveESLVSAvoidcapacitor characteristics

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent extracts the conductor arrangement from the through-hole structure and repositions conductors to extend vertically from the electrode portions directly to the mounting terminals on the surface. This extraction eliminates the need for through-holes that penetrate the capacitor body, thereby preserving capacitor characteristics while achieving the ESL reduction benefit of multi-terminal configuration.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of passing conductors through the capacitor body from one side to the other (conventional approach), the patent inverts the arrangement by having conductors extend from the electrode portions upward to the mounting terminals on the same surface. This inverted configuration maintains electrical connectivity while avoiding the harmful effects of through-hole construction on capacitor performance.

Inventive Principle:

Principle #13The other way round (Inversion)

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 design effectively reduces ESL while maintaining capacitor characteristics, simplifying production and enabling easier mass production by eliminating the need for through holes and reducing production complexity.

Implementation Method 1

a dielectric layer formed on a surface of the base member and made of an oxide of a metal component of the base member

Methodology Applied

Scientific EffectDielectric breakdown: Dielectric

Implementation Method 2

a first insulating resin layer and a second insulating resin layer

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

a cathode conductor layer and an anode conductor layer formed on the first and the second regions, respectively

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS7457103B2Solid electrolytic capacitor which can easily be lowered in ESL

Publication Date: 2008.11.25 TOKIN CORP

AI summary

In a solid electrolytic capacitor including a device portion having a cathode conductor layer and an anode conductor layer arranged on a sheet-like or a foil-like base member, a first insulating resin layer is formed on the cathode conductor layer and the anode conductor layer. A positive electrode mounting terminal layer is formed on the first insulating resin layer. An anode conductor portion penetrates the first insulating resin layer to electrically connect the positive electrode mounting terminal layer to the anode conductor layer. A plurality of negative electrode mounting terminal layers are arranged on the first insulating resin layer. A cathode conductor portion penetrates the first insulating resin layer to electrically connect the negative electrode mounting terminal layer to the cathode conductor layer. A second insulating resin layer is formed on the positive electrode mounting terminal layer. The second insulating resin layer has a plurality of first opening portions partially exposing the positive electrode mounting terminal layer.