Electrolytic Capacitor Anode Lead Layout for Lower ESR

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Solution Overview

Problem

Existing electrolytic capacitors face challenges in reducing equivalent series resistance (ESR), which affects their high-frequency characteristics and overall performance.

Innovation Solution

The electrolytic capacitor design includes a porous anode body with a sheet-shaped anode lead, a dielectric layer, a cathode layer, an anode lead frame, and a cathode lead frame, where the anode lead is positioned between the center and end face of the anode body, enhancing the connection interface and reducing ESR by increasing the conductive path area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the anode lead is positioned at the center of the anode body, then the structural symmetry is improved, but the equivalent series resistance (ESR) increases due to longer current path length

Engineering Contradiction:
Improvestructural symmetryVSAvoidequivalent series resistance
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The anode lead is intentionally positioned asymmetrically within the anode body, specifically located between the center and the end face rather than at the exact center. This asymmetric positioning shortens the current path length from the anode body to the anode lead frame, thereby reducing the equivalent series resistance while maintaining adequate structural stability

Inventive Principle:
Principle #4Asymmetry

2Loss of energy

If the anode lead is positioned closer to the end face of the anode body, then the equivalent series resistance (ESR) is reduced due to shorter current path length, but the connection interface area with the anode body decreases

Engineering Contradiction:
Improveequivalent series resistanceVSAvoidconnection interface area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The anode lead is positioned in a specific local region between the center and the end face of the anode body. This location provides an optimal balance where the connection interface area is sufficiently large to ensure good electrical contact, while the distance to the end face remains short enough to minimize the current path length and reduce ESR

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11984271B2Electrolytic capacitor having reduced equivalent series resistance
Publication Date: 2024.05.14 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • US11984271B2 patent drawing
  • US11984271B2 patent drawing
  • US11984271B2 patent drawing

AI summary

An electrolytic capacitor includes an anode body having a porous structure, an anode lead having a sheet shape, a cathode layer, an anode lead frame electrically connected to the anode lead, and a cathode lead frame electrically connected to the cathode layer. The anode lead includes an embedded portion embedded in the anode body and a protrusion portion protruding to an outside of the anode body. The anode lead has a first main surface facing the cathode lead frame and a second main surface opposite to the first main surface. The anode lead is located between a center of the anode body and an end face of the anode body in a first direction in which the first main surface faces the cathode lead frame. The end face of the anode body is positioned at a side close to the cathode lead frame.