Externally Fused Safe Capacitor with Resistive Load

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing capacitor designs face challenges in failing safely to prevent damage to circuits due to material compatibility issues between Precious Metal Electrodes (PME) and Base Metal Electrodes (BME) systems, and the high cost and complexity of integrating resistors and fuses with capacitors using thick film technology.

Innovation Solution

A safe capacitor design incorporating a ceramic substrate with a resistor and/or fuse connected in parallel or series with one or more capacitors, allowing for a resistive load failure mode and rapid discharge, compatible with both PME and BME metallization technologies, and manufactured using cost-effective methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If thick film technology is used to integrate resistors and fuses with capacitors, then functional integration is achieved, but manufacturing cost and complexity increase significantly

Engineering Contradiction:
Improvefunctional integrationVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the capacitor structure into separate functional segments: the capacitor element and the safe circuit (resistor and fuse) are integrated as distinct but connected components. This segmentation allows each component to be optimized independently while achieving functional integration, reducing manufacturing complexity compared to monolithic thick film integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary approach by using a substrate that can receive both capacitor elements and safe circuit components. This substrate acts as a mediator that facilitates integration without requiring complex thick film processes, thereby reducing manufacturing complexity while maintaining functional integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If individual capacitor printing is performed, then precise circuit patterns are achieved, but extensive tooling and automation are required

Engineering Contradiction:
Improvecircuit pattern precisionVSAvoidtooling and automation requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple printing operations into a single integrated process by applying both capacitor and safe circuit patterns in one printing step. This consolidation maintains circuit pattern precision while eliminating the need for extensive tooling and automation between separate printing steps, thereby reducing manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal printing approach that can produce both capacitor elements and safe circuit patterns using the same printing system. This multi-functional printing method achieves precise circuit patterns without requiring specialized tooling for different components, reducing automation requirements and simplifying manufacturing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution provides reliable performance at elevated temperatures, design flexibility, and cost-effective integration of safe circuits with capacitors, preventing damage from catastrophic failures and ensuring safe discharge of energy.

Implementation Method 1

BME systems, which typically utilize nickel, are dramatically less expensive and are therefore preferred. Unfortunately, BME systems must be fired in a reducing atmosphere in order to keep the nickel from oxidizing.

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

thick film materials are designed to be fired in an air atmosphere

Methodology Applied
Scientific EffectFiring: Heat Treatment

Implementation Method 3

Thin film metallization is based on vapor deposition of materials onto a surface.

Methodology Applied
Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentEP2471079B1Externally fused and resistively loaded safe capacitor
Publication Date: 2016.01.06 KEMET ELECTRONICS CORP
  • EP2471079B1 patent drawingFigure 1~2
  • EP2471079B1 patent drawingFigure 3~5
  • EP2471079B1 patent drawingFigure 6~8

AI summary

A capacitor combined with a resistor and/or fuse is described. This safe capacitor can rapidly discharge through the resistor when shorted. The presence of a fuse in series with the capacitor results in a resistive failure when the fuse opens during an overcurrent condition. Furthermore, the presence of a resistor in parallel to the capacitor allows the energy to be rapidly dissipated when a failure occurs.