Multilayer Capacitor Dummy Electrode Corner Moisture Resistance
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Solution Overview
Problem
Multilayer capacitors face issues with moisture and ion penetration through their corner portions, leading to deterioration of insulating resistance and reliability, particularly in high-capacity devices with many laminated sheets.
Innovation Solution
The introduction of dummy electrodes on the upper and lower cover layers, exposed through the corners of the capacitor body, which are spaced apart and connected to the external electrodes, enhances moisture resistance by blocking penetration and improving the fixing strength of the external electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitor body is made with many laminated sheets to increase capacity, then the capacitance is improved, but the corner portions become more susceptible to moisture and ion penetration
Solution Approach 1:
The patent applies different structural treatments to different parts of the capacitor body. Specifically, dummy electrodes are added only at the corner portions where moisture penetration occurs, while the central active areas maintain their original electrode structure. This localized modification protects vulnerable corners without affecting the overall capacitance or requiring changes to the entire capacitor structure.
Solution Approach 2:
The dummy electrodes are positioned in advance at the corner portions of the capacitor body, creating a protective barrier before moisture and ions can penetrate. This preliminary structural arrangement prevents harmful substances from reaching the internal electrodes, thereby maintaining reliability in high-capacity designs with many laminated sheets.
2Ease of manufacture
If the external electrode thickness is reduced at corner portions to facilitate mounting, then the ease of mounting is improved, but moisture and ion penetration increases
Solution Approach 1:
The patent maintains thin external electrodes at corner portions for ease of mounting while simultaneously adding dummy electrodes at these same corner locations. The dummy electrodes create a protective barrier that compensates for the reduced thickness, preventing moisture and ion penetration while preserving the mounting advantages of thinner corner electrodes.
3Reliability
If dummy electrodes are added at corner portions to block moisture penetration, then the moisture resistance is improved, but the device complexity increases
Solution Approach 1:
The capacitor structure is segmented into active areas and corner portions, with dummy electrodes added only at the corner segments. This segmentation allows the protective function to be isolated to specific locations rather than requiring a comprehensive redesign of the entire capacitor structure, thereby minimizing the increase in device complexity.
Solution Approach 2:
The dummy electrodes are implemented as a simple local modification at the corner portions rather than a comprehensive structural change. This localized approach adds minimal complexity to the overall device while effectively addressing the moisture penetration issue at the vulnerable corner areas.
Data Source
AI summary
A multilayer capacitor may include a capacitor body including an active area including a plurality of dielectric layers, and a plurality of first and second internal electrodes, upper and lower cover layers disposed on upper and lower surfaces of the active area, and having first to six external surfaces; first and second external electrodes including first and second connection portions and first and second band portions, respectively; and a plurality of dummy electrodes disposed on the upper and lower cover layers with a dielectric layer interposed therebetween, and exposed through corners of the capacitor body, a portion of the plurality of dummy electrodes being disposed between the upper and lower surfaces of the capacitor body and the first and second band portions.