Conductive Paste Phenoxy Resin Solid Electrolytic Capacitor
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Solution Overview
Problem
Solid electrolytic capacitors face issues with interlayer peeling and crack generation in the solid electrolyte layer due to stress during the curing process of conventional conductive pastes, leading to deteriorated equivalent series resistance (ESR) characteristics.
Innovation Solution
A conductive paste comprising a conductive filler, a thermosetting resin with a phenoxy resin having a molecular weight of 30000 to 100000, and a curing agent, which reduces stress and shrinkage during curing, preventing cracks in the solid electrolyte layer and improving ESR characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conductive paste with epoxy resin is used to form the electrode layer, then the adhesion with the solid electrolyte layer is improved and the resistance value is reduced, but stress during curing causes interlayer peeling and crack generation in the solid electrolyte layer, deteriorating ESR characteristics
Solution Approach 1:
The patent changes the chemical composition parameters of the conductive paste by replacing epoxy resin with phenoxy resin, which has different curing characteristics and lower shrinkage stress. This parameter change resolves the contradiction by maintaining adhesion and conductivity while reducing the harmful stress that causes peeling and cracking, thereby improving ESR characteristics without compromising structural integrity.
Solution Approach 2:
The patent uses a composite material approach by formulating a conductive paste that combines phenoxy resin with conductive fillers (silver powder, copper powder, or flake silver powder). This composite material provides both the adhesion needed to prevent peeling and the conductivity needed to reduce resistance, while the phenoxy resin matrix minimizes curing stress to prevent crack generation in the solid electrolyte layer.
2Ease of manufacture
If the molecular weight of the phenoxy resin is small, then the viscosity is low and ease of manufacture is improved, but shrinkage at curing increases causing large stress on the solid electrolyte layer
Solution Approach 1:
The patent optimizes the molecular weight parameter of the phenoxy resin to fall within the specific range of 30,000 to 100,000. This parameter optimization achieves a balance where the resin has sufficiently low viscosity for ease of manufacture and application, while simultaneously maintaining low shrinkage stress during curing to prevent damage to the solid electrolyte layer. The specific molecular weight range resolves the contradiction between processability and stress control.
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 use of the conductive paste with a phenoxy resin and curing agent effectively reduces stress and shrinkage, resulting in solid electrolytic capacitors with enhanced ESR characteristics and reduced risk of microcracks, enabling better performance and downsizing of capacitors.
Implementation Method 1
a conductive paste including at least a conductive filler, a thermosetting resin containing a phenoxy resin, and a curing agent
Data Source
AI summary
A solid electrolytic capacitor that includes a valve action metal base, an insulating layer, a solid electrolyte layer, a carbon layer and an electrode layer sequentially formed in one of two parts of the valve action metal base. The electrode layer is formed from a conductive paste that includes at least a conductive filler, a thermosetting resin containing a phenoxy resin, and a curing agent.