Misaligned Solid Electrolyte Capacitor Stack Reduces ESR
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Solution Overview
Problem
Conventional solid electrolytic capacitors with precisely aligned elements face challenges in achieving optimal electric properties, particularly in reducing equivalent series resistance (ESR) and leakage current (LC), due to limitations in encapsulation and alignment techniques.
Innovation Solution
The capacitors employ a novel structure where cathode parts of stacked elements are intentionally misaligned, with one end part of each element being more prominent or retracted than the adjacent element, allowing for improved electrical connections and reduced encapsulation damage, using a conductive paste to fill the gaps between the cathode terminal and the prominent or retracted ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If capacitor elements are stacked precisely aligned one on another, then manufacturing precision is improved, but electric properties (ESR and leakage current) deteriorate
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning capacitor elements in the stacked configuration. Specifically, adjacent capacitor elements are positioned such that their cathode parts do not align perfectly, creating an asymmetric stacked structure. This asymmetric arrangement improves electric properties by reducing equivalent series resistance and leakage current, while maintaining acceptable manufacturing precision through controlled misalignment within specified tolerances.
2Reliability
If encapsulation is applied to prevent incomplete sealing, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by providing protrusions on the capacitor elements before encapsulation. These protrusions are formed in advance during element fabrication, creating mechanical interlocking features that ensure complete sealing and prevent incomplete encapsulation. This preliminary structural preparation simplifies the encapsulation process while maintaining high reliability, as the protrusions guide the encapsulant material and ensure proper filling without requiring complex encapsulation procedures.
3Productivity
If multiple elements are stacked to achieve predetermined capacitance, then productivity is improved, but electric properties (ESR and leakage current) deteriorate
Solution Approach 1:
The patent applies asymmetry in the stacking arrangement of multiple capacitor elements to simultaneously achieve high productivity and maintain excellent electric properties. By configuring adjacent elements with intentional misalignment where cathode parts do not perfectly overlap, the structure reduces equivalent series resistance and leakage current even when multiple elements are stacked. This allows efficient achievement of predetermined capacitance values while maintaining low ESR and leakage current, resolving the contradiction between productivity and electric property quality.
Data Source
AI summary
A solid electrolytic capacitor, including a stack of solid electrolytic capacitor elements each having an anode part and a cathode part. The stacked structure is such that cathode parts of solid electrolytic capacitor elements are stacked one on another to have some misalignment between the stacked elements. The capacitor preferably has a structure in which one end part of the cathode part of at least one of the solid electrolytic capacitor elements stacked on another element is more prominent or retracted than that of the element below.