Aluminum Electrolytic Capacitor Electrolyte Leakage Prevention

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Solution Overview

Problem

Aluminum electrolytic capacitors face leakage issues due to alkali deterioration at high temperatures and high humidity, which existing solutions do not adequately address, compromising their reliability.

Innovation Solution

An electrolytic solution comprising an aprotic solvent, a quaternized amidine-based cation, and a specific compound that forms an amine salt to neutralize OH- ions, preventing alkali-induced deterioration and leakage, with a preferred composition of 1,2,3,4-tetramethylimidazolinium/phthalate monoanion and 4-methoxybutyric acid to enhance heat resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If quaternary alkylammonium-based electrolytic solution is used, then the electrolytic capacitor can operate, but the sealing member deteriorates due to alkali and electrolytic solution leaks

Engineering Contradiction:

Improveelectrolytic capacitor operationVSAvoidalkali deterioration of sealing member

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful OH- ions generated during capacitor operation into a beneficial effect by introducing a compound that reacts with OH- to form a protective coating on the sealing member. The harmful alkali that causes deterioration is transformed into a protective layer that prevents further damage and leakage.

Inventive Principle:

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

Solution Approach 2:

The patent introduces a compound as an intermediary substance that mediates between the harmful OH- ions and the sealing member. This compound reacts with OH- to form an amine salt that coats the sealing member, acting as a protective barrier that prevents direct contact between alkali and the sealing material.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If amidine-based electrolytic solution is used, then alkali-caused deterioration is suppressed, but suppression efficiency is insufficient at high temperature and high humidity

Engineering Contradiction:

Improvealkali-caused deterioration suppressionVSAvoidsuppression efficiency at high temperature and humidity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the electrolytic solution by introducing a specific compound with amine functional groups. This compound has high reactivity with OH- ions, forming a protective coating that is particularly effective at high temperatures and humid conditions where conventional amidine-based solutions fail.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If compound (E) is added to neutralize OH- ions, then sealing member protection is enhanced, but electrolytic solution composition becomes more complex

Engineering Contradiction:

Improvesealing member protectionVSAvoidelectrolytic solution composition

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by concentrating the protective function in a specific compound (E) that selectively reacts with OH- ions at the sealing member interface. This compound is introduced in a controlled amount (0.01-5 wt%) to provide localized protection where it is most needed, without significantly complicating the overall electrolytic solution composition.

Inventive Principle:

Principle #3Local quality

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 effectively prevents electrolyte leakage from sealed parts even at high temperatures and high humidity, ensuring the reliability and longevity of aluminum electrolytic capacitors, particularly in automotive applications.

Implementation Method 1

a compound (E) represented by formula (2)... which reacts with OH- generated when a voltage is applied to the electrolytic solution to form an amine salt

Methodology Applied

Scientific EffectChemical reaction (amine salt formation): Chemical Bonding

Implementation Method 2

OH- generated when a voltage is applied to the electrolytic solution

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP2843673B1Electrolytic solution for aluminum electrolytic capacitor, and aluminum electrolytic capacitor using same

Publication Date: 2019.01.16 SANYO CHEM IND LTD

AI summary

In order to render an electrolytic solution not leak from a sealed part even at a higher temperature of the environment or in a high-humidity condition to enhance the reliability of an electrolytic capacitor, an electrolytic solution for an aluminum electrolytic capacitor is described. The electrolytic solution includes an aprotic solvent (A), an electrolyte (D) containing a salt composed of a cation (B) represented by formula (1) and an anion (C), and a compound (E) represented by formula (2) and having a content of 0.01 to 3 wt% relative to the total weight of (A) and (D): wherein in formulae (1) and (2), R1 to R3 are each C1-3 alkyl, R4 to R7 are each C1-3 alkyl or a hydrogen atom, and R8 to R14 are each C1-3 alkyl or a hydrogen atom.