Solid Electrolytic Capacitor Terminal With Nested Collecting Portion
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Solution Overview
Problem
Conventional solid electrolytic capacitors face challenges in increasing capacitance and reducing equivalent series resistance (ESR) while preventing conductive resin from being exposed, which can lead to short circuits on circuit boards during thinning of the resin package.
Innovation Solution
The design incorporates a negative terminal with a mount portion, a protruding portion, and a collecting portion to accommodate the conductive bonding portion, reducing its exposure and allowing for a larger capacitance and smaller ESR by containing the conductive bonding portion within the terminal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the resin package is thinned to reduce capacitor thickness, then the thickness parameter is improved, but the conductive bonding portion becomes exposed on the mounting surface causing short circuits
Solution Approach 1:
The conductive bonding portion is nested within the hollow cavity of the collecting portion of the negative terminal. This nesting structure allows the conductive bonding material to be contained inside the terminal rather than extending to the exterior, enabling the resin package to be thinned without exposing the conductive bonding portion that could cause short circuits.
2Strength
If the conductive bonding portion is increased in thickness to improve bonding strength, then the strength is improved, but the thickness increases causing exposure on the mounting surface
Solution Approach 1:
The hollow cavity of the collecting portion provides internal space that accommodates a thicker conductive bonding portion. This allows the bonding strength to be increased by using more bonding material while the material remains contained within the terminal structure, preventing exposure on the mounting surface even when the resin package is thinned.
3Quantity of substance
If the capacitance is increased to meet demand, then the capacitance parameter is improved, but the equivalent series resistance (ESR) decreases making it harder to maintain low ESR
Solution Approach 1:
The negative electrode is designed with a porous structure that increases its surface area. This porous structure allows the capacitance to be increased by providing more surface for charge storage while the conductive polymer electrolyte penetrates the porous structure to maintain good electrical contact, thereby keeping the equivalent series resistance low despite the increased capacitance.
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 configuration effectively prevents the conductive bonding portion from being exposed, enabling the creation of solid electrolytic capacitors with high capacitance and low ESR, thus enhancing packaging efficiency and preventing short circuits.
Implementation Method 1
The ESR of element 51 thus is small. In addition, a surface where a dielectric oxide film is formed is etched.
Data Source
AI summary
A solid electrolytic capacitor includes a capacitor element, a negative terminal, a positive terminal, and a resin package covering the capacitor element. The negative terminal and the positive terminal are joined respectively to a negative electrode section and a positive electrode section of the capacitor element. The negative terminal has a mount portion, a protruding portion, and a collecting portion. The mount portion has the negative electrode section disposed thereon, and is joined to an underside of the negative electrode via a conductive bonding portion. The protruding portion protrudes from a side edge of the mount portion in a same plane as the mount portion, and has a width narrowed stepwise in a protruding direction. The collecting portion is provided adjacent to a side edge of a part where the protruding portion is narrowed stepwise, and accommodates a part of the conductive bonding portion.