Solid Electrolytic Capacitor Via Electrode Thickness Reduction
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Solution Overview
Problem
Existing solid electrolytic capacitors face challenges in increasing the volume ratio of the capacitance formation part to the overall capacitor volume, making it difficult to produce thin capacitors.
Innovation Solution
The design includes a capacitor element with a valve-acting metal substrate, a porous part, a dielectric layer, a solid electrolyte layer, and conductive layers, where anodic and cathodic via electrodes are formed to penetrate sealing resin and insulating layers, allowing the core part to be electrically connected to the surface, and outer electrodes are arranged on the sealing resin, eliminating the need for thick electrodes like mount boards or lead frames, thereby reducing overall thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional production methods with mount boards or lead frames are used, then electrical connection is achieved, but the overall thickness of the capacitor increases
Solution Approach 1:
The patent removes the traditional mount board or lead frame structure from the capacitor design. Instead, the external electrodes are formed directly on the sealing resin surface, and internal connections are established through via electrodes embedded in the sealing resin, eliminating the need for separate mounting structures and reducing overall thickness.
Solution Approach 2:
The patent transitions from a planar connection architecture (mount boards) to a three-dimensional architecture where via electrodes penetrate the sealing resin to establish vertical electrical connections. This dimensional change allows compact integration and reduces the thickness requirement.
2Volume of moving object
If the volume of non-capacitance formation layers is reduced, then volumetric efficiency of the capacitance formation part increases, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into the sealing resin: it provides mechanical sealing, electrical insulation, and serves as the substrate for forming via electrodes and external electrodes. This integration eliminates separate mounting structures and reduces the volume occupied by non-capacitance layers while maintaining manufacturability through conventional molding processes.
Solution Approach 2:
The sealing resin is designed to perform multiple functions simultaneously: structural support, electrical insulation, moisture barrier, and electrode substrate. This multi-functionality reduces the need for additional components and minimizes the volume of non-capacitance formation layers.
3Reliability
If via electrodes are formed to penetrate sealing resin, then electrical connection to core part is achieved, but vapor resistance and adhesion requirements increase
Solution Approach 1:
The patent employs composite material structures in the via electrodes, combining different materials with complementary properties. The via electrodes are formed with materials that provide both excellent electrical conductivity and high adhesion to the sealing resin, while the sealing resin itself is selected for its superior vapor resistance properties, creating a composite system that meets all requirements.
Data Source
AI summary
A solid electrolytic capacitor includes a valve-acting metal substrate including a core part and a porous part disposed on at least one principal surface of the core part. A dielectric layer is formed in a surface of the porous part and a solid electrolyte layer is disposed on the dielectric layer. A conductive layer is disposed on the solid electrolyte layer and a sealing resin seals a principal surface of the capacitor element. A cathodic outer electrode is electrically connected to the conductive layer and an anodic outer electrode is electrically connected to the core part. An insulating layer is interposed between the core part and the sealing resin. The insulating layer, the sealing resin, and the anodic outer electrode are disposed on and above the core part in this order. A first anodic via electrode is formed in the sealing resin disposed on the insulating layer so as to penetrate the sealing resin. A second anodic via electrode is formed in the insulating layer disposed on the core part so as to penetrate the insulating layer. The core part is electrically drawn to a surface of the sealing resin through the first and second anodic via electrodes. The first anodic via electrode exposed at the surface of the sealing resin is connected to the anodic outer electrode.