Wound Electrolytic Capacitor Layout for Lower ESR
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Solution Overview
Problem
Existing electrolytic capacitors with wound electrode foils face increased equivalent series resistance (ESR) due to elevated electric resistance, which is not sufficiently reduced by current manufacturing methods, especially when handling high frequency and large ripple currents.
Innovation Solution
Incorporating a current collector connected to the non-facing portion of the electrode foil at the end of the wound body, which reduces the distance electrical charges need to travel, thereby minimizing resistance and heat generation, and using a conductive polymer to enhance electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a wound body obtained by winding electrode foil is used as a capacitor element, then the capacitor can be manufactured with compact structure, but electric resistance increases and ESR increases
Solution Approach 1:
The electrode foil is divided into multiple independent conductive paths by forming protruding portions. These protruding portions create separate current flow paths that reduce the overall electrical resistance. The segmentation of the continuous foil into multiple parallel paths allows current to distribute more efficiently, lowering ESR while maintaining the compact wound structure.
Solution Approach 2:
Protruding portions are formed on the surface of the electrode foil, adding a vertical dimension to the otherwise planar structure. This three-dimensional configuration increases the effective surface area for current collection and creates multiple current flow paths through the wound body, reducing electrical resistance without increasing the overall footprint of the capacitor.
2Reliability
If thermal spraying metal on the protruding portion is applied, then electrical conductivity is enhanced, but manufacturing complexity increases
Solution Approach 1:
The surface properties of the protruding portions are modified through thermal spraying, changing the material parameters to enhance electrical conductivity. By depositing metal coating on the protruding portions, the electrical conductivity is improved without fundamentally altering the manufacturing process flow, thus balancing performance enhancement with manufacturing feasibility.
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
The solution effectively reduces ESR, allowing for efficient handling of high ripple currents and improved heat dissipation, making the electrolytic capacitor more suitable for high-frequency applications.
Implementation Method 1
using a conductive polymer to enhance electrical conductivity
Data Source
AI summary
An electrolytic capacitor includes a capacitor element, a first current collector, and a case. The capacitor element includes a wound body in which a first electrode foil and a second electrode foil are wound. The first electrode foil and the second electrode foil face each other. The first current collector is connected to the first electrode foil. The case houses the capacitor element and the first current collector. The first electrode foil includes a first facing portion that faces the second electrode foil and a first non-facing portion that does not face the second electrode foil. The first non-facing portion is located at a first end portion in a winding axis of the wound body. The first current collector is disposed in a vicinity of the first end portion of the wound body to be connected to the first non-facing portion of the first electrode foil.