Electrolytic Solution Copolymer for High Voltage Capacitors

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Solution Overview

Problem

Existing electrolytic capacitors face challenges in achieving high voltage resistance, high initial conductivity, and excellent heat resistance, with existing solutions providing insufficient improvements in electrical conductivity and voltage resistance.

Innovation Solution

An electrolytic solution for electrolytic capacitors is developed, comprising an electrolyte with an anion obtained by removing hydrogen ions from a carboxy group of a copolymer with specific substituents and a solvent containing ethylene glycol, ensuring the copolymer meets certain conductivity and molecular weight conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a salt of 1,6-decanedicarboxylic acid is used as an electrolyte, then high temperature stability is improved, but the electrical conductivity is insufficient and voltage resistance is not high

Engineering Contradiction:
Improvehigh temperature stabilityVSAvoidvoltage resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses a copolymer electrolyte comprising multiple monomer units (acrylic acid, methacrylic acid, and a specific ester monomer) rather than a single compound. This composite polymer structure combines the benefits of different functional groups to achieve both high temperature stability and high voltage resistance simultaneously, resolving the contradiction between thermal stability and electrical performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for the copolymer composition (monomer ratios, molecular weight, carboxyl group content) and electrolyte concentration (10-30 wt%). By optimizing these parameters, the electrolyte achieves both high temperature stability and high voltage resistance, transforming the insufficient performance of conventional single-compound electrolytes into superior dual-performance characteristics.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional electrolytes are used, then manufacturing is simple, but both initial conductivity and voltage resistance are insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidinitial conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent maintains manufacturing simplicity by using a copolymerization process with well-established chemistry, while dramatically improving initial conductivity through parameter optimization: specifying 10-30 wt% electrolyte concentration, controlling carboxyl group content at 0.5-2.0 mmol/g, and setting molecular weight between 1,000-50,000. These parameter changes enable high initial conductivity without complicating the manufacturing process.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If electrolyte concentration is increased to improve conductivity, then initial conductivity improves, but voltage resistance and heat resistance deteriorate

Engineering Contradiction:
Improveinitial conductivityVSAvoidheat resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent identifies an optimal electrolyte concentration range of 10-30 wt% that simultaneously achieves high initial conductivity (0.2-3.0 mS/cm) and excellent heat resistance. This parameter optimization prevents the trade-off where higher concentration improves conductivity but harms thermal stability, as the copolymer structure maintains stability within this optimized concentration window.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The copolymer electrolyte's composite structure with specific monomer composition (including ester groups and carboxyl groups in controlled ratios) enables the electrolyte to maintain both high conductivity and heat resistance at the same concentration level, unlike conventional electrolytes that require compromising one property for the other.

Inventive Principle:
Principle #40Composite materials

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 results in electrolytic capacitors with high voltage resistance, high initial conductivity, and excellent heat resistance, as demonstrated by improved electrical conductivity retention and sparking voltage performance.

Implementation Method 1

the electrolyte contains an anion and a cation, and the anion is an anion having a structure obtained by removing at least one hydrogen ion from a carboxy group from a copolymer having a carboxy group

Methodology Applied
Scientific EffectIon transport: Electrolysis

Data Source

PatentUS11424078B2Electrolytic solution for electrolytic capacitor, and electrolytic capacitor
Publication Date: 2022.08.23 SANYO CHEM IND LTD

AI summary

An electrolytic solution for an electrolytic capacitor comprising an electrolyte and a solvent, in which the electrolyte contains an anion and a cation, and the anion is an anion having a structure obtained by removing at least one hydrogen ion from a carboxy group from a copolymer having a carboxy group, the copolymer having a carboxy group has a substituent having 5-20 carbon atoms bonded to a carbon atom of a backbone of the copolymer, the copolymer having a carboxy group does not include a hydroxy group or if it does include a hydroxy group, the content of monomers including a hydroxy group in the structural monomers of the copolymer having a carboxy group is less than 60 wt % based on the weight of all monomers constituting the copolymer having a carboxy group, and the copolymer satisfies a specific condition, and the solvent contains ethylene glycol.