Stacked Solid Electrolytic Capacitor Joining Layout for Stable ESR
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Solution Overview
Problem
Existing stacked solid electrolytic capacitors face issues with inconsistent equivalent series resistance (ESR) due to poor connection quality between anode leads, which is not adequately addressed in prior art.
Innovation Solution
A solid electrolytic capacitor design featuring multiple joining portions with varying areas on different surfaces, including a first joining portion with a larger area on one surface and a second joining portion with a smaller area on the other surface, connected through a crimping and welding process, to enhance electrical connectivity between stacked anode portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple capacitor elements are stacked together, then the capacitance value increases, but the connection quality between anode leads deteriorates leading to ESR variation
Solution Approach 1:
The anode lead connection structure is segmented into multiple distinct joining portions (first joining portion and second joining portion) with different areas. This segmentation allows each portion to contribute differently to the electrical connection, ensuring reliable connectivity while accommodating the stacking of multiple capacitor elements. The first joining portion with larger area provides primary connection stability, while the second joining portion with smaller area provides additional connection paths, collectively reducing ESR variation as capacitor elements are stacked.
2Ease of manufacture
If joining portions have uniform area, then manufacturing is simplified, but ESR variation increases due to insufficient connection quality
Solution Approach 1:
The joining portions are designed with different areas to create local quality variations in the connection structure. The first joining portion has a larger area optimized for primary electrical connection and mechanical stability, while the second joining portion has a smaller area providing supplementary connection paths. This local differentiation in joining portion areas ensures consistent ESR values across stacked capacitor elements while maintaining manufacturability through a systematic design approach.
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 significantly reduces variation in ESR by improving the joining quality between anode portions, resulting in more consistent electrical resistance values across capacitors.
Implementation Method 1
a temporary fixing step of temporarily fixing the stacked anode portions having a first surface and a second surface that are located outermost on one side and another side, respectively, in a stacking direction by crimping the stacked anode portions together in the stacking direction with the anode lead terminal
Implementation Method 2
a joining step of forming three of more joining portions that join and electrically connect the plurality of temporarily fixed anode portions together, wherein the three or more joining portions include a first joining portion having a first area on the first surface and a second joining portion having a second area smaller than the first area on the first surface, and in the joining step, the first joining portion is formed by welding from the first surface, and the second joining portion is formed by welding from the second surface
Data Source
AI summary
A solid electrolytic capacitor 10 disclosed herein includes: a plurality of capacitor elements 11 stacked on top of each other, each capacitor element having an anode portion 13 and a cathode portion 14; an anode lead terminal 17 electrically connected to at least one of the anode portions 13; and three or more joining portions 20 joining and electrically connecting the stacked anode portions 13 together. The stacked anode portions 13 have a first surface 13a and a second surface 13b that are located outermost on one side and the other side, respectively, in the stacking direction. The three or more joining portions 20 include a first joining portion 21 having a first area on the first surface 13a and a second joining portion 22 having a second area smaller than the first area on the first surface 13a. Thus, variation in ESR can be reduced.