Multilayer Ceramic Capacitor Layout for Failure Detection and Thermal Shock

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Solution Overview

Problem

Conventional multilayer capacitors lack the ability to detect failures such as short circuits, which can occur after mounting, and do not provide adequate protection against thermal shock and stress, leading to potential cracks and short circuits.

Innovation Solution

A multilayer capacitor design where first and second capacity parts are connected in series through third internal electrodes and a connection conductor, with the connection conductor disposed on the lateral surface to prevent short circuits, and resin electrode layers on external electrodes for thermal shock resistance and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If capacitor components are connected in series to improve withstand voltage, then reliability is improved, but the ability to detect failures is lost

Engineering Contradiction:
Improvewithstand voltage characteristicVSAvoidfailure detection capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The capacitor is divided into multiple capacitor components connected in series, with each component having its own external electrodes. This segmentation allows individual components to be identified and monitored, enabling failure detection while maintaining series connection for improved withstand voltage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

External electrodes are introduced as intermediaries between the capacitor components. These external electrodes provide access points for measuring capacitance and resistance values of individual components, enabling failure detection without disrupting the series connection configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If connection conductor is disposed on mounting surface to simplify structure, then ease of manufacture is improved, but short circuit risk increases

Engineering Contradiction:
Improvestructural simplicityVSAvoidshort circuit occurrence
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The connection conductor is moved from the mounting surface to the lateral surface of the capacitor. This dimensional relocation eliminates the risk of short circuits with circuit board electrodes during mounting, while still maintaining electrical connection between capacitor components through the lateral surface routing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If external electrodes lack resin coating to reduce complexity, then device complexity is reduced, but thermal shock resistance decreases

Engineering Contradiction:
Improveelectrode structure complexityVSAvoidthermal shock resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Resin is applied as a coating layer on the external electrodes, creating a composite structure that combines the conductive properties of the electrode material with the protective and flexible properties of the resin. This composite structure provides thermal shock resistance and stress relief without significantly increasing overall device complexity.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3454352B1Multilayer ceramic capacitor
Publication Date: 2024.04.24 TDK CORP
  • EP3454352B1 patent drawingFigure 1
  • EP3454352B1 patent drawingFigure 2
  • EP3454352B1 patent drawingFigure 3

AI summary

A multilayer capacitor (1) includes an element (2), a first external electrode (3), a second external electrode (4), and a plurality of internal electrodes. The plurality of internal electrodes include first internal electrodes (12), second internal electrodes (14), and a plurality of third internal electrodes (16). The plurality of third internal electrodes (16) are electrically connected by a connection conductor (5). First capacity parts (C1) are constituted of the first internal electrodes (12) and the third internal electrodes (16), and second capacity parts (C2) are constituted of the second internal electrodes (12) and the third internal electrodes (16). The first capacity part (C1) and the second capacity part (C2) are electrically connected in series, and the connection conductor (5) is disposed on at least one of the three lateral surfaces other than the lateral surface that is a mounting surface, among the four lateral surfaces.