Capacitor Base and Resin Interface for Electrolyte Gas Venting
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Solution Overview
Problem
The gap between the resin layer and the outer sealing member in capacitors can allow electrolytic solution to seep in, leading to reduced insulation resistance and compromised capacitor reliability due to conductive electrolyte between terminal leads.
Innovation Solution
A capacitor design where the base and resin layer have a non-adherent interface, with a gas path formed between them, allowing electrolyte gas to escape, and the resin layer's adhesive force to the base is weaker than thermal deformation forces, ensuring the resin layer separates during mounting, preventing electrolyte retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resin layer adheres to the base, then the sealability is enhanced, but electrolytic solution may accumulate in gaps causing insulation resistance to decrease
Solution Approach 1:
The base is segmented into multiple protruding portions that divide the space between the base and opening sealing member into multiple regions. This segmentation prevents electrolytic solution from accumulating in large continuous gaps, as the protruding portions act as barriers to solution flow and accumulation zones.
Solution Approach 2:
The protruding portions serve as intermediary structures between the base and opening sealing member. These intermediaries create controlled pathways that allow electrolytic solution gas to escape while preventing liquid electrolyte from accumulating in harmful gaps, thus mediating between the conflicting requirements of sealability and solution drainage.
2Temperature
If the resin layer forms a sealed layer, then heat resistance is improved, but gas passage is blocked causing electrolyte to return
Solution Approach 1:
The resin layer is applied with locally different properties: in some regions it forms a sealed adhesive layer for heat resistance, while in other regions (at the protruding portions) it creates controlled gaps for gas passage. This local differentiation allows the resin layer to simultaneously provide thermal protection and gas venting functionality.
Solution Approach 2:
The solution moves from a two-dimensional planar resin layer to a three-dimensional structured arrangement with protruding portions. This dimensional change creates vertical spacing and pathways that allow gas to escape through the resin layer structure without compromising the overall sealing and heat resistance function.
3Ease of operation
If the base includes insertion through holes for terminal leads, then mounting is enabled, but resin may flow into holes causing mounting issues
Solution Approach 1:
The protruding portions are pre-formed on the base before resin layer application. This preliminary action creates physical barriers that prevent resin from flowing into the insertion through holes during the resin injection process, thus preventing mounting issues before they occur.
Solution Approach 2:
The protruding portions extract or remove the problematic function of resin flow into holes by creating separate zones. The resin is confined to specific regions between the base and opening sealing member, while the insertion through holes remain clear for terminal lead passage, thus separating the resin containment function from the hole function.
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 design effectively prevents electrolyte gas from staying between terminal leads, maintaining insulation resistance and enhancing capacitor stability by allowing gas to escape and reducing resin layer adhesion to the base, thus improving reliability.
Implementation Method 1
The base and the resin layer are in contact with or spaced apart from each other without at least partly adhering to each other... a boundary portion between the base and the resin layer may include contact surfaces, spaced-apart surfaces, or contact surfaces and spaced-apart surfaces, of the base and the resin layer, and the boundary portion may form a gas path for allowing passage of gas
Implementation Method 2
If the base further includes a protruding portion that separates the insertion through holes and the resin layer, the protruding portion suppresses flowing-in of resin for generating the resin layer to the insertion through holes
Implementation Method 3
an adhesive force of the resin layer to the base is smaller than a force that thermal deformation at a mounting processing is to generate between the base and the resin layer
Data Source
AI summary
A capacitor (2) includes a capacitor main body (4), a base (6), and a resin layer (8-1). The capacitor main body includes an outer package case (10), an opening sealing member (14) attached to an opening of the outer package case, and a terminal lead (16-1, 16-2) extending through the opening sealing member. The base is disposed toward the opening sealing member of the capacitor main body and includes an insertion through hole (18-1, 18-2) into which the terminal lead is inserted to be exposed on a mounting surface side, and a protruding portion (20) surrounding the insertion through hole. The resin layer is arranged at least between the base and the opening sealing member. The base and the resin layer are in contact with or spaced apart from each other without at least partly adhering to each other.