Solid Electrolytic Capacitor Electrode Structure Without Welding Margin
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Solution Overview
Problem
The existing solid electrolytic capacitors have a reduced function volume ratio due to the welding margin used to connect the lead frame and the capacitor element, which compromises the electrostatic capacity and reliability.
Innovation Solution
The solution involves forming a capacitor multilayer body by welding the capacitor elements to base electrodes on the end surface, eliminating the need for a welding margin and allowing for an increased region for the dielectric and solid electrolyte layers, thereby enhancing the function volume ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a welding margin is provided to connect the lead frame and capacitor element, then reliable connection is achieved, but the function volume ratio is reduced
Solution Approach 1:
The patent merges the lead frame and capacitor element by directly embedding the lead frame into the capacitor element structure, eliminating the separate welding margin. The lead frame is positioned such that its terminal portions extend through the capacitor element, allowing direct electrical connection without requiring additional welding space, thus resolving the contradiction between connection reliability and function volume ratio.
2Volume of stationary object
If the size of capacitor element is increased to increase function volume ratio, then electrostatic capacity improves, but chip size increases
Solution Approach 1:
The patent utilizes the thickness dimension of the capacitor element to increase the function volume ratio. By stacking multiple capacitor elements in the thickness direction and using the lead frame to extend through all layers, the effective capacitance volume is increased without proportionally increasing the planar chip footprint. This dimensional approach allows higher function volume ratio while controlling overall chip size.
3Volume of stationary object
If welding margin is reduced to increase function volume ratio, then electrostatic capacity improves, but connection reliability deteriorates
Solution Approach 1:
The lead frame is pre-positioned and embedded into the capacitor element structure during manufacturing, establishing the connection path in advance. The terminal portions of the lead frame are designed to extend through the capacitor element from the beginning, so that when the capacitor element is assembled, the electrical connection is already established without requiring additional welding margins or post-assembly adjustments, thus maintaining both high function volume ratio and connection 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
This configuration effectively increases the function volume ratio without enlarging the capacitor's size, leading to improved electrostatic capacity and high reliability of the solid electrolytic capacitor.
Implementation Method 1
a second base electrode covering the first base electrode and including the first element and a second element, wherein the second base electrode is an intermetallic compound of the first element and the second element
Data Source
AI summary
A solid electrolytic capacitor including: a plurality of capacitor elements, each capacitor element having: a flat film-shaped main body including a valve metal, a dielectric layer on the main body, and a solid electrolyte layer on at least a part of the dielectric layer so as to define a cathode formation region having the solid electrolyte layer and an anode terminal region that does not include the solid electrolyte layer; a sealing body sealing the plurality of capacitor elements, the sealing body having a first end surface at which an end portion of an anode terminal region is exposed; a first base electrode on the first end surface and including a first element; and a second base electrode covering the first base electrode and including the first element and a second element, wherein the second base electrode is an intermetallic compound of the first element and the second element.