Multilayer Capacitor Open Mode Electrodes Flexible Terminations

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Solution Overview

Problem

Multilayer ceramic capacitors are prone to cracking due to thermal and mechanical stress, which can lead to unwanted electrical connections between electrodes, causing shorts.

Innovation Solution

The capacitors feature a monolithic body with large margin distances between electrodes and external terminations made of a conductive polymeric composition, which reduces stress and prevents cracks from intersecting electrodes, ensuring the capacitors fail open and avoid electrical shorts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multilayer capacitors are formed with traditional electrode configurations and terminations, then manufacturing is simplified, but thermal and mechanical stress causes cracks that intersect electrodes near margins, leading to electrical shorts

Engineering Contradiction:

Improveelectrical isolationVSAvoidelectrode configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The capacitor structure is segmented into distinct regions: internal electrodes confined to a central region, and separate termination regions at opposite ends. This segmentation ensures that cracks forming in termination regions cannot intersect internal electrodes, maintaining electrical isolation even under stress

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Margin regions act as intermediary zones between internal electrodes and external terminations. These margin regions absorb thermal and mechanical stress, preventing stress transmission to the internal electrodes, thereby preventing crack formation that would cause electrical shorts

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If margin distances between electrodes and terminations are increased to prevent cracks from intersecting electrodes, then electrical isolation is improved, but device length increases

Engineering Contradiction:

Improvecrack resistanceVSAvoidcapacitor length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The design optimizes the margin ratio parameter (body length to margin distance) to be greater than 10, establishing a quantitative threshold that ensures adequate stress buffer zones while controlling overall device dimensions. This parameter change balances reliability requirements with size constraints

Inventive Principle:

Principle #35Parameter changes

3Reliability

If external terminations are made with conductive polymeric composition to reduce stress, then crack prevention is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvestress resistanceVSAvoidtermination fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

External terminations are constructed using conductive polymeric composition, which combines the electrical conductivity needed for terminal function with the mechanical flexibility and stress-absorbing properties of polymeric materials. This composite material approach provides superior stress resistance compared to traditional rigid conductive materials

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 design enhances the robustness and resilience of the capacitors, preventing electrical connections and maintaining electrical isolation even under stress, thus reducing the risk of shorts.

Implementation Method 1

external terminations made of a conductive polymeric composition, which reduces stress and prevents cracks from intersecting electrodes

Methodology Applied

Scientific EffectStress reduction:

Data Source

PatentUS11705280B2Multilayer capacitor having open mode electrode configuration and flexible terminations

Publication Date: 2023.07.18 KYOCERA AVX COMPONENTS CORP

AI summary

A multilayer ceramic capacitor may include a monolithic body and interleaved first and second pluralities of electrodes extending from the first and second ends, respectively, of the monolithic body towards opposite ends of the monolithic body. A first margin distance and a second margin distance may be formed, respectively, between the electrodes and the opposite ends of the monolithic body. First and second external terminations may be respectively disposed along the first end and second end of the monolithic body and respectively connected with the first and second plurality of electrodes. A margin ratio between a length of the monolithic body and the first margin distance and/or second margin distance may be less than about 10. At least one of the first external termination or the second external termination may include a conductive polymeric composition.