Integrated Multilayer Capacitor with Overcurrent Protection

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Solution Overview

Problem

Existing electronic components with multilayer capacitors face issues with overcurrent flow during short-circuit conditions, leading to potential damage and vibration-induced noise due to electrostrictive effects.

Innovation Solution

Incorporating an overcurrent protection device in series with the multilayer capacitor, utilizing a PTC thermistor or fuse with internal electrodes and external electrodes connected via leg portions to absorb vibrations and prevent overcurrent flow, while maintaining design flexibility and low connection resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multilayer capacitor is used without an overcurrent protection device, then the device complexity is low and manufacturing is simple, but overcurrent can flow during short-circuit conditions causing damage

Engineering Contradiction:

Improveovercurrent protectionVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the multilayer capacitor and overcurrent protection device into a single integrated component. The capacitor element and protection element share a common first element body, with internal electrodes directly connected through conductive layers without requiring external connection components. This merging reduces device complexity while maintaining overcurrent protection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The first element body serves multiple functions: it provides the structural housing for the capacitor, contains the dielectric layers and internal electrodes, and also houses the protection circuit element. This multi-functionality reduces the overall component count and structural complexity while ensuring reliable overcurrent protection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If external connection components are used to connect the capacitor and protection device, then design flexibility is reduced and mounting area increases, but connection reliability can be ensured

Engineering Contradiction:

Improveconnection simplicityVSAvoidconnection reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent eliminates external connection components by integrating the protection device directly within the capacitor structure. The fourth external electrode is formed on the same element body as the first, second, and third external electrodes, creating direct internal connections without requiring separate mounting or connection components. This simplifies manufacturing while ensuring reliable electrical connection.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If the protection circuit element is disposed outside the element body, then layout design flexibility is reduced, but the element structure remains simple

Engineering Contradiction:

Improvelayout flexibilityVSAvoidelement structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The protection circuit element is nested within the first element body, utilizing the internal space of the capacitor structure. The element body contains both the capacitor's dielectric layers and the protection element, with all internal electrodes and conductive layers integrated within the same housing. This nesting approach maximizes layout flexibility while maintaining structural simplicity.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

Effectively prevents overcurrent flow during short-circuits and suppresses vibration-induced noise, ensuring reliable operation and reduced risk of damage to electronic devices without increasing mounting area.

Implementation Method 1

Incorporating an overcurrent protection device in series with the multilayer capacitor, utilizing a PTC thermistor or fuse

Methodology Applied

Scientific EffectPTC (Positive Temperature Coefficient) effect: Thermistor

Implementation Method 2

Incorporating an overcurrent protection device in series with the multilayer capacitor, utilizing a PTC thermistor or fuse

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

utilizing a PTC thermistor or fuse with internal electrodes and external electrodes connected via leg portions to absorb vibrations and prevent overcurrent flow

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentUS9916929B2Electronic component

Publication Date: 2018.03.13 TDK CORP

AI summary

A first metal terminal includes a first connection portion connected to an electrode portion of a second external electrode, and a first leg portion extending from the first connection portion. A second metal terminal includes a second connection portion connected to a conductor portion of a connection conductor, and a second leg portion extending from the second connection portion. A multilayer capacitor and an overcurrent protection device are disposed in such a manner that a first principal surface and a third side surface oppose each other. An electrode portion of a first external electrode and an electrode portion of a fourth external electrode are connected to each other.