Electrolytic Capacitor Liquid Polymer for Low ESR at High Heat

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Solution Overview

Problem

Existing electrolytic capacitors face issues with heat resistance due to the degradation of polyalkylene glycol, leading to permeation and oxidation of the conductive polymer component, which increases equivalent series resistance (ESR) and leak current.

Innovation Solution

Incorporating a first polymer component with a carbon chain lacking heteroatoms except at the terminal and containing at least 50% (meth)acrylic acid-based and vinyl alcohol-based units, which suppresses main chain cutting and permeation, thereby protecting the conductive polymer and maintaining conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polyalkylene glycol is used as the electrolytic solution component, then the electrolytic capacitor can operate at high temperatures, but the polyalkylene glycol undergoes main chain cutting and permeation through the sealing body, leading to oxidation degradation of the conductive polymer component and increased ESR

Engineering Contradiction:

Improveheat resistanceVSAvoidconductive polymer stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

A protective coating layer is applied to the sealing body to act as an intermediary barrier. This coating prevents the degraded polyalkylene glycol (with reduced molecular weight) from permeating through the sealing body and reaching the conductive polymer component, thereby protecting the conductive polymer from oxidation while maintaining high-temperature operation capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters of the electrolytic solution by specifying particular types of polyalkylene glycol (different molecular weights and structures) and adjusting their proportions. This parameter optimization reduces the extent of main chain cutting at high temperatures and minimizes permeation through the sealing body, thereby maintaining conductive polymer stability while enabling high-temperature operation

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If the electrolytic solution contains polyalkylene glycol, then the capacitor can maintain low ESR, but the polyalkylene glycol permeates through the sealing body at high temperatures, causing oxidation of the conductive polymer and increasing ESR

Engineering Contradiction:

Improveequivalent series resistanceVSAvoidoxidation degradation

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The protective coating on the sealing body serves as an intermediary barrier that blocks the pathway for degraded polyalkylene glycol to reach the conductive polymer component. This prevents oxidation reactions that would increase ESR, while allowing the electrolytic solution to maintain its low-ESR properties through proper polyalkylene glycol selection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent accepts that polyalkylene glycol will undergo some degradation at high temperatures but converts this potential harm into a benefit by selecting specific polyalkylene glycol types that, even when degraded, do not become sufficiently small to permeate the sealing body. The degradation products remain too large to cause oxidation, thus maintaining low ESR over time

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances heat resistance by reducing permeation and oxidation degradation, maintaining low ESR and improving withstand voltage, even under high-temperature conditions.

Implementation Method 1

suppresses main chain cutting and permeation, thereby protecting the conductive polymer and maintaining conductivity

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

oxidation degradation of the conductive polymer component may progress

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS12562317B2Electrolytic capacitor and liquid component for electrolytic capacitor

Publication Date: 2026.02.24 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An electrolytic capacitor includes a capacitor element and a liquid component. The capacitor element includes an anode body including a dielectric layer on a surface of the anode body, and a solid electrolyte layer covering at least a part of a surface of the dielectric layer. The solid electrolyte layer contains a conductive polymer component, and the liquid component contains a first polymer component. The first polymer component includes a carbon chain whose main chain does not contain a heteroatom at a position other than a terminal of the main chain. Units constituting the first polymer component include at least one first unit selected from the group consisting of a (meth)acrylic acid-based unit having a carboxy group and a vinyl alcohol-based unit having a hydroxy group. A proportion of the at least one first unit in an entirety of the units constituting the first polymer component is more than 50 mass %.