Electrolytic Capacitor Solid Electrolyte Layer Cracking Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solid electrolytic capacitors with polyvinyl alcohol in the solid electrolyte layer suffer from cracking, leading to inadequate leakage current suppression, insufficient withstand voltage, and high equivalent series resistance (ESR) due to poor film quality and conductivity.
Innovation Solution
A two-layer structure for the solid electrolyte layer, comprising a first conductive polymer layer and a second conductive polymer layer with a water-soluble polymer, which forms a three-dimensional network to enhance strength, reduce cracking, and improve conductivity, thereby increasing withstand voltage and reducing ESR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyvinyl alcohol is added to the solid electrolyte layer to impart adhesion, then adhesion between dielectric layer and solid electrolyte layer is improved, but the solid electrolyte layer develops cracks and film quality deteriorates
Solution Approach 1:
The invention removes polyvinyl alcohol from the solid electrolyte layer composition entirely. Instead of using the problematic binder, the patent relies on the intrinsic adhesion properties of the conductive polymer itself and uses a water-soluble polymer additive that does not cause cracking, thereby extracting the harmful element while maintaining necessary adhesion.
Solution Approach 2:
The invention changes the chemical composition parameters of the solid electrolyte layer by eliminating polyvinyl alcohol and introducing a water-soluble polymer with specific molecular weight and functional group characteristics. This parameter change transforms the material properties to achieve both adhesion and crack resistance simultaneously.
2Strength
If conventional solid electrolyte layer composition is used, then adhesion is provided, but equivalent series resistance (ESR) increases and conductivity decreases
Solution Approach 1:
The invention extracts polyvinyl alcohol from the solid electrolyte composition, which was causing increased ESR and reduced conductivity. By removing this problematic binder and using only conductive polymer with appropriate dopants and water-soluble polymer additives, the electrical conductivity is improved while adhesion is maintained through alternative mechanisms.
3Ease of manufacture
If solid electrolyte layer is formed without water-soluble polymer, then manufacturing is simpler, but withstand voltage is insufficient and cracking occurs
Solution Approach 1:
The invention creates a composite solid electrolyte layer by combining conductive polymer, high-molecular-weight dopant, and water-soluble polymer in specific proportions. This composite structure provides both the electrical conductivity needed for low ESR and the mechanical strength needed for high withstand voltage, while the water-soluble polymer enhances adhesion without causing cracking.
4Strength
If polyvinyl alcohol is used as binder, then adhesion is improved, but film quality deteriorates and leakage current suppression becomes insufficient
Solution Approach 1:
The invention removes polyvinyl alcohol from the formulation, eliminating the source of film quality deterioration and cracking. Adhesion is achieved through the conductive polymer's inherent properties and the water-soluble polymer additive, which does not compromise film integrity or leakage current suppression.
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 proposed solution effectively enhances the strength and conductivity of the solid electrolyte layer, leading to improved withstand voltage and reduced ESR in electrolytic capacitors, while preventing cracking and maintaining high film quality.
Implementation Method 1
a water-soluble polymer, which forms a three-dimensional network to enhance strength, reduce cracking, and improve conductivity
Implementation Method 2
The solid electrolyte layer includes a π-conjugated conductive polymer, a high-molecular-weight dopant having an acid group
Implementation Method 3
a high-molecular-weight dopant having an acid group
Data Source
AI summary
An electrolytic capacitor includes an anode body, a dielectric layer formed on the anode body, and a solid electrolyte layer covering at least a portion of the dielectric layer. The solid electrolyte layer includes a π-conjugated conductive polymer, a high-molecular-weight dopant having an acid group, and a water-soluble polymer. The water-soluble polymer is a copolymer including a hydrophilic monomer unit having a hydrophilic group. The hydrophilic group is at least one group selected from the group consisting of a carboxyl group, an acid anhydride group, a phenolic hydroxyl group, and a C2-3 alkylene oxide group.