Porous Metal Capacitor Sealing With Water-Repellent Interlayer
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Solution Overview
Problem
Existing capacitors with a metal porous body, dielectric film, and conductive film face issues of plating solution residue causing blister formation and stress, leading to dielectric film cracking and potential short circuits due to metal porous body dissolution.
Innovation Solution
A capacitor design with a conductive interposing film interposed between the capacitance forming part and the plating part, sealed by an insulating substrate and plating part, preventing plating solution intrusion and enhancing reliability by minimizing stress on the capacitance forming part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plating part is formed to seal the capacitance forming part, then sealing performance is improved, but plating solution residue remains in fine spaces causing blister formation and stress
Solution Approach 1:
A water repellent film is introduced as an intermediary layer between the capacitance forming part and the plating part. This film prevents plating solution from penetrating into the fine spaces of the capacitance forming part while allowing the plating part to form properly, thus eliminating residue accumulation and blister formation while maintaining sealing performance
Solution Approach 2:
The patent converts the potentially harmful plating solution residue into a beneficial sealing mechanism. By allowing controlled plating solution contact with the water repellent film (which repels the solution), the system uses the plating process itself to form a protective plating part that seals the capacitance forming part, transforming the harmful residue issue into a beneficial sealing feature
2Reliability
If plating solution expands due to thermal load, then sealing is enhanced, but stress causes dielectric film cracking
Solution Approach 1:
The water repellent film serves as a stress-isolating intermediary layer between the capacitance forming part and the plating part. When plating solution expands due to thermal load, this film prevents direct stress transmission to the dielectric film, avoiding cracking while maintaining the sealing function through the plating part
3Ease of manufacture
If plating solution contacts metal porous body, then plating part formation is facilitated, but metal porous body dissolves causing short circuit
Solution Approach 1:
The water repellent film acts as a protective intermediary that allows the plating part to form on its outer surface while preventing plating solution from contacting and dissolving the metal porous body inside the capacitance forming part, thus maintaining both manufacturability and reliability
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 design effectively suppresses short circuits and maintains capacitor function by preventing plating solution intrusion and peeling, ensuring improved reliability post-mounting.
Implementation Method 1
a water repellent film that covers the conductive film in a portion defining a space inside the capacitance forming part
Data Source
AI summary
A capacitor that includes: an insulating substrate having a first main surface; a capacitance forming part on the main surface, the capacitance forming part including a conductive metal porous body, a dielectric film covering a surface of the conductive metal porous body, and a conductive film covering the dielectric film; a first external connection line connected to the conductive metal porous body; and a second external connection line connected to the conductive film, the second external connection line including a conductive plating part on an outer peripheral part of the capacitance forming part, and a conductive interposing film interposed between the capacitance forming part and the plating part, wherein the capacitance forming part is sealed by the insulating substrate and the conductive plating part.