Metal-Oxide-Coated Separator for High-Temperature Electrolytic Capacitors

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Solution Overview

Problem

Existing electrolytic capacitors experience significant deterioration in characteristics, particularly an increase in equivalent series resistance (ESR), at high temperatures, which affects their reliability and performance.

Innovation Solution

The use of an electrolytic capacitor design where at least part of the separator is coated with a conductive metal oxide, such as indium tin oxide, which enhances the separator's strength and heat resistance, thereby reducing ESR and maintaining capacitor characteristics at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional separators are used in electrolytic capacitors, then the structure is simple and manufacturing is easy, but the equivalent series resistance (ESR) increases significantly at high temperatures causing deterioration in characteristics

Engineering Contradiction:

Improvecharacteristic stability at high temperatureVSAvoidseparator structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The separator is constructed as a composite material consisting of a base separator (first separator) and a conductive metal oxide coating layer (second separator) formed on its surface. This composite structure combines the mechanical strength and thermal stability of the base separator with the electrical conductivity of the metal oxide layer, thereby reducing ESR at high temperatures while maintaining structural integrity and manufacturing feasibility.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the separator is coated with conductive metal oxide to reduce ESR, then characteristic deterioration at high temperatures is suppressed, but the manufacturing process becomes more complex

Engineering Contradiction:

ImproveESR stability at high temperatureVSAvoidseparator coating process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The conductive metal oxide coating layer is formed by controlling specific parameters including thickness (0.1-10 μm), porosity (30-70%), and metal oxide content (1-50 wt%). By optimizing these parameters, the coating process achieves the desired ESR reduction while maintaining compatibility with existing manufacturing processes, balancing performance improvement with manufacturing ease.

Inventive Principle:

Principle #35Parameter changes

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 approach effectively suppresses the deterioration of electrolytic capacitor characteristics at high temperatures, reducing ESR and maintaining performance, thus enhancing the capacitor's reliability and longevity.

Implementation Method 1

at least part of the separator is coated with a conductive metal oxide

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

enhances the separator's strength and heat resistance, thereby reducing ESR and maintaining capacitor characteristics at high temperatures

Methodology Applied

Scientific EffectThermal resistance: Thermal Insulation

Data Source

PatentUS12293878B2Electrolytic capacitor and production method therefor

Publication Date: 2025.05.06 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Disclosed is an electrolytic capacitor including an anode body, a dielectric layer formed on the anode body, a cathode body, and a separator and an electrolyte that are disposed between the dielectric layer and the cathode body. At least part of the separator is coated with a conductive metal oxide.