Solid Electrolytic Capacitor Stress Grooves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multi-layered solid electrolytic capacitors face issues with stress buildup at the boundary between the anode and cathode portions due to thickness differences, leading to increased leakage current and defects from cracks, which existing solutions like resin application or tape attachment fail to adequately alleviate, resulting in reduced product yield and increased manufacturing costs.
Innovation Solution
The introduction of stress alleviating grooves or holes between the welded parts and the boundary between the anode and cathode portions reduces bending stress, preventing cracks and leakage current without increasing capacitor size or manufacturing costs, with the grooves or holes being strategically formed and shaped to optimize stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the anode portion and cathode portion are stacked with different thicknesses to achieve compact design, then the capacitor size is reduced, but stress buildup occurs at the boundary causing cracks and leakage current
Solution Approach 1:
The anode portion is segmented by introducing stress alleviating grooves or holes that divide the continuous structure into sections. This segmentation allows differential movement between the anode and cathode portions, reducing stress concentration at the boundary while maintaining the overall compact structure.
Solution Approach 2:
The stress alleviating grooves or holes are strategically positioned only at critical stress concentration points (the boundary between anode and cathode portions) rather than throughout the entire structure. This localized modification reduces stress where needed while preserving the structural integrity and compactness of the rest of the capacitor.
2Reliability
If resin is applied or tape is attached to alleviate stress at the boundary, then stress buildup is reduced, but the capacitor size and manufacturing cost increase
Solution Approach 1:
Instead of adding external stress-alleviating components like resin or tape, the invention extracts or removes material from the anode portion itself by creating grooves or holes. This approach reduces stress while simultaneously reducing the overall capacitor volume, opposite to the conventional additive approach.
Solution Approach 2:
The stress alleviating grooves or holes are formed using laser processing, which creates precise geometric features that replicate the stress-distribution function of larger external components but in a miniaturized, integrated form that maintains compact dimensions.
3Reliability
If resin is applied to alleviate stress, then stress buildup is reduced, but additional drying process and material cost are incurred
Solution Approach 1:
The anode portion structure itself provides the stress-alleviation function through its built-in grooves or holes, eliminating the need for external resin materials and associated drying processes. The structure serves its own stress-management needs without requiring additional manufacturing steps or materials.
Solution Approach 2:
The mechanical stress-alleviation function previously achieved by applying resin (a material-based solution) is replaced by a geometric structural solution (grooves or holes). This substitution eliminates the need for material application and drying processes, simplifying manufacturing and reducing costs.
4Reliability
If tape is attached to alleviate stress, then stress buildup is reduced, but precise bonding is troublesome and capacitor size increases
Solution Approach 1:
The invention removes the need for external tape components by extracting stress-alleviation functionality directly into the anode structure through grooves or holes. This eliminates the complex tape bonding process and associated precision requirements while maintaining stress management.
Solution Approach 2:
The grooves or holes act as an internal intermediary structure within the anode portion that mediates stress distribution. This internal mediator replaces the external tape mediator, eliminating the need for precise bonding operations while achieving the same stress-alleviation effect.
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 approach significantly improves product yield by preventing leakage current and defects while maintaining manufacturing efficiency and cost-effectiveness, as the capacitors are designed with grooves or holes that allow for controlled bending and reduced stress, ensuring reliable performance without size or cost increments.
Implementation Method 1
tensile stress and bending stress act on the boundary between the anode portion 7 and the cathode portion 8 or on the vicinity thereof (indicated by reference numeral 50 in FIG. 15) during the resistance welding, and the stresses build up in that part
Implementation Method 2
the anode portion 7 of the capacitor element 6 is connected to the anode terminal 12 by resistance welding, and then, the connected anode portion 7 of the capacitor element 6 is welded to the anode portion 7 of another capacitor element 6
Data Source
AI summary
A multi-layered solid electrolytic capacitor and a method of manufacturing the capacitor that improve the product yield drastically by preventing increases in leakage current and defects due to short circuits without increasing manufacturing cost or capacitor size. A multi-layered solid electrolytic capacitor includes: a plurality of capacitor elements, each including an aluminum foil having an anode portion and a cathode portion having a dielectric oxide film and a cathode layer formed in succession on a surface of the aluminum foil, wherein the plurality of capacitor elements are stacked on top of one another, the anode portions of adjacent capacitor elements are welded each other, and the anode portion of one of the outermost capacitor elements is weld-secured to an anode terminal, the multi-layered solid electrolytic capacitor having a first stress alleviating groove and a second stress alleviating groove formed in at least one of weld surfaces of the anode portion.