Hydrophobic Coated Anode Lead Wire for Delamination-Resistant Capacitors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid electrolytic capacitors face delamination issues due to residual moisture vaporization during high-temperature manufacturing, leading to rapid deterioration of electrical properties.
Innovation Solution
A solid electrolytic capacitor design featuring a sintered porous anode body, a dielectric layer, and a solid electrolyte, with an anode lead wire having a hydrophobic coating and recessed regions to enhance adhesion and prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature reflow is used during capacitor manufacture, then manufacturing process is completed, but residual moisture vaporizes causing micro-cracks and delamination
Solution Approach 1:
The anode lead wire surface is pre-treated with a hydrophobic coating and recessed region formation before the reflow process. This preliminary preparation allows the lead wire to repel moisture vapor during subsequent high-temperature processing, preventing the vapor from penetrating into the casing material and causing delamination.
Solution Approach 2:
The hydrophobic coating on the anode lead wire converts the harmful effect of moisture vapor into a beneficial outcome by actively repelling the vapor during high-temperature reflow. The coating transforms what would be a damaging condition (moisture exposure at high temperature) into a protective mechanism that prevents delamination while allowing the manufacturing process to proceed.
2Ease of manufacture
If conventional anode lead wire design is used, then manufacturing is simple, but delamination occurs at high temperatures
Solution Approach 1:
The surface properties of the anode lead wire are modified by applying a hydrophobic coating and creating recessed regions. These parameter changes in surface chemistry and topology enable the lead wire to resist moisture vapor adhesion during thermal processing, significantly improving thermal stability without complicating the overall manufacturing process.
Solution Approach 2:
The recessed regions created on the anode lead wire surface provide a textured, porous-like structure that enhances the effectiveness of the hydrophobic coating. This surface geometry prevents moisture vapor from making direct contact with the bulk lead wire material, reducing capillary action and adhesion forces that would otherwise cause delamination at high temperatures.
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 capacitor exhibits improved electrical performance with reduced equivalent series resistance and capacitance stability at high temperatures and humidity levels, maintaining performance over extended periods.
Implementation Method 1
A hydrophobic coating is disposed on at least a portion of the external surface of the anode lead wire
Data Source
AI summary
A solid electrolytic capacitor that comprises a capacitor element that contains a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric is provided. An anode lead wire extends from the capacitor element in a longitudinal direction, wherein the lead wire defines an external surface having a plurality of distinct recessed regions that are spaced apart along the longitudinal direction. A hydrophobic coating is disposed on at least a portion of the external surface of the anode lead wire. Further, an anode termination is in electrical connection with the anode lead wire and a cathode termination is in electrical connection with the solid electrolyte.