MLCC Electrode Segmentation for Stress Mitigation

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Solution Overview

Problem

Multi-layer ceramic capacitors (MLCCs) face dielectric breakdown due to piezoelectric and electrostrictive stress induced by high voltage, which causes microscopic fissures or cracks, limiting their reliability in applications like electric vehicle charging systems.

Innovation Solution

The electrical components feature a layered structure with interleaved electrodes separated by gaps and a dielectric body, reducing voltage-induced stress through strategic electrode placement and spacing, which can include uniform or varying spacings and offset gaps to mitigate electrostrictive and piezoelectric stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high voltage is applied to MLCCs, then power delivery is improved, but piezoelectric and electrostrictive stress induces microscopic fissures or cracks causing dielectric breakdown

Engineering Contradiction:

Improvepower deliveryVSAvoiddielectric breakdown resistance

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The electrode is divided into multiple discrete portions separated by gaps instead of being continuous. This segmentation reduces the concentration of piezoelectric and electrostrictive stress, preventing the formation of microscopic fissures and cracks that lead to dielectric breakdown under high voltage conditions

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If continuous electrodes are used, then manufacturing simplicity is maintained, but stress concentration causes dielectric breakdown

Engineering Contradiction:

Improveelectrode fabrication simplicityVSAvoidbreakdown performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The electrode structure is segmented into discrete portions with gaps between them. This can be implemented through standard printing and firing processes by controlling the electrode material distribution to create gaps, maintaining manufacturing feasibility while improving reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode structure transitions from uniform continuity to localized discontinuity, with gaps strategically positioned at intervals along the electrode length. This local modification of electrode quality reduces stress concentration at critical points while maintaining overall electrode functionality

Inventive Principle:

Principle #3Local quality

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 configuration enhances the breakdown performance of electrical components by reducing stress-induced fissures and cracks, thereby improving reliability and durability under high voltage conditions.

Implementation Method 1

The ceramic dielectric of such capacitors however is subject to piezoelectric and electrostrictive stress that is known to induce microscopic fissures or cracks

Methodology Applied

Scientific EffectPiezoelectric stress: Piezoelectric Effect

Implementation Method 2

The ceramic dielectric of such capacitors however is subject to piezoelectric and electrostrictive stress that is known to induce microscopic fissures or cracks

Methodology Applied

Scientific EffectElectrostrictive stress: Electrostriction

Data Source

PatentUS11670453B2Electrical component having layered structure with improved breakdown performance

Publication Date: 2023.06.06 KNOWLES UK LTD

AI summary

An electrical component having a layered structure including first and second electrodes each having first and second electrode portions located in a plane and at least partially embedded in a dielectric body, each of the first and second electrode portions separated by a gap and substantially isolated by the dielectric, the first electrode substantially parallel to and at least partially overlapping the second electrode, wherein the first and second electrodes are electrically isolated and separated by the dielectric body.