Solid Electrolytic Capacitor Multilayer Cathode ESR Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid electrolytic capacitors face challenges in achieving low equivalent series resistance (ESR) in high frequency bands due to high contact resistance between cathode layers, particularly in multilayer structures.
Innovation Solution
A solid electrolytic capacitor is designed with a first cathode layer made of polyethylenedioxythiophene (PEDOT) and polypyrrole (PPy), and a second cathode layer of PPy, where the PEDOT coverage on the dielectric layer is optimized between 0% and 80%, and the cathode layers are formed through chemical polymerization and electrolytic polymerization processes, respectively, using specific oxidizing agents and temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer cathode structure is used, then the capacitance and stability are improved, but the contact resistance between layers increases the ESR
Solution Approach 1:
The patent applies local quality by creating distinct regions within the cathode layer with different compositions and functions. The first cathode layer uses polypyrrole with high conductivity to minimize contact resistance at the interface with the dielectric layer, while the second cathode layer uses polythiophene or its derivatives for stable capacitance. This spatial differentiation of material properties resolves the contradiction between low contact resistance and high capacitance stability.
Solution Approach 2:
The patent employs composite materials by combining different conducting polymer materials in a multilayer structure. The first cathode layer is made of polypyrrole (PPy) and the second cathode layer is made of polythiophene or its derivatives, creating a composite structure that leverages the high conductivity of PPy and the stable capacitance of polythiophene to simultaneously reduce ESR and maintain capacitance stability.
2Ease of manufacture
If the cathode layer is made of a single material, then the manufacturing process is simplified, but the conductivity and capacitance stability cannot be optimized simultaneously
Solution Approach 1:
The patent applies segmentation by dividing the cathode into two distinct layers with different materials and functions. The first cathode layer (polypyrrole) focuses on providing high conductivity and low contact resistance, while the second cathode layer (polythiophene or derivatives) focuses on providing stable capacitance. This functional segmentation allows each layer to be optimized for its specific purpose while maintaining a relatively simple overall manufacturing process.
3Object-affected harmful factors
If PEDOT coverage is increased to improve conductivity, then the contact resistance decreases, but the capacitance is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of PEDOT within the first cathode layer. Rather than uniformly increasing PEDOT coverage throughout, the invention optimizes the local concentration and distribution of PEDOT to achieve sufficient conductivity while preserving capacitance in other regions. This localized optimization resolves the contradiction between reducing contact resistance and maintaining capacitance.
Solution Approach 2:
The patent employs composite materials by combining PEDOT with other conducting polymer materials in the first cathode layer. This composite approach allows the PEDOT to provide conductivity and reduce contact resistance, while the other materials contribute to maintaining capacitance, thus resolving the contradiction between low contact resistance and high capacitance.
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 configuration reduces the ESR of the solid electrolytic capacitor by improving conductivity and minimizing contact resistance between the cathode layers, thereby enhancing its performance in high frequency applications.
Implementation Method 1
performing a first oxidation process for attaching an oxidizing agent to a surface of the dielectric layer
Implementation Method 2
allowing the vapor of ethylenedioxythiophene monomer to react with the oxidizing agent on the surface of the dielectric layer
Implementation Method 3
performing a first heating process for heating the ethylenedioxythiophene monomer allowed to react with the oxidizing agent
Implementation Method 4
allowing the vapor of pyrrole monomer to react with the oxidizing agent on the surface of the dielectric layer
Data Source
AI summary
A solid electrolytic capacitor includes an anode substrate, a dielectric layer provided on the anode substrate, a first cathode layer provided on the dielectric layer, and a second cathode layer provided on the first cathode layer. The first cathode layer is a layer made of polyethylenedioxythiophene and polypyrrole. The second layer is a layer made of polypyrrole.