Capacitor Separator Structure Using Low-Cost Pulp Without Short Circuits
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Solution Overview
Problem
The challenge is to develop a separator for aluminum electrolytic capacitors that uses inexpensive fibers such as malvaceae, tiliaceae, and poaceae pulps, while maintaining excellent short-circuit resistance performance and impedance characteristics, as traditional materials like Manila hemp and esparto pulps are scarce and expensive, and existing alternatives like malvaceae, tiliaceae, and poaceae pulps suffer from poor strength and impedance due to wide, short parenchymal cells.
Innovation Solution
A separator configuration using malvaceae, tiliaceae, and poaceae pulps, with a short-circuit rate of no more than 10% at 500 V during dielectric breakdown testing, achieved by reducing parenchymal cells through multiple cylinder paper machine layers and controlled pulp suspension concentration, and optimizing fiber length and density to enhance tensile strength and impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If malvaceae, tiliaceae, and poaceae pulps are used as separator materials, then cost is reduced and availability is improved, but short-circuit resistance and impedance characteristics deteriorate due to wide and short parenchymal cells
Solution Approach 1:
The patent applies parameter changes by controlling the beating degree of the pulp fibers and optimizing the fiber suspension concentration during papermaking. By adjusting these parameters, the parenchymal cells are broken down into smaller fragments, transforming the fiber structure to achieve both cost-effectiveness and electrical performance. The beaten fiber structure with reduced parenchymal cell integrity prevents short circuits while maintaining affordability.
Solution Approach 2:
The patent uses composite materials by combining different types of pulp fibers (malvaceae, tiliaceae, and/or poaceae) in specific ratios. This composite approach allows the separator to leverage the cost advantages of these abundant fibers while compensating for their individual weaknesses through synergistic combinations, achieving both economic and electrical performance requirements.
2Productivity
If wood pulp is used as separator material, then production amount is large and stable availability is achieved, but impedance characteristics worsen due to flat cross-sectional shape and large size
Solution Approach 1:
The patent transforms the fiber morphology parameter changes by applying intensive beating treatment to wood pulp fibers. This process changes the flat, large cross-sectional shape into a more rounded, thinner structure, improving impedance characteristics while maintaining the production advantages of wood pulp. The beating degree is controlled to achieve optimal fiber transformation.
3Reliability
If solvent-spun cellulose fiber is used as separator material, then impedance characteristics are improved due to circular cross-sectional shape and thin diameter, but cost increases making it unsuitable as a substitute
Solution Approach 1:
The patent applies the principle of using cheap, readily available natural fiber materials (malvaceae, tiliaceae, and poaceae pulps) instead of expensive solvent-spun cellulose fibers. By processing these inexpensive fibers through controlled beating and optimization of papermaking parameters, the patent achieves impedance characteristics comparable to premium materials while maintaining cost-effectiveness for mass production.
4Ease of manufacture
If parenchymal cells are present in separator made of malvaceae, tiliaceae, and poaceae pulps, then manufacturing is simplified, but tensile strength and tear strength deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the beating degree and fiber suspension concentration to control the fragmentation of parenchymal cells. Rather than completely eliminating them (which would simplify manufacturing further but reduce strength), the patent finds an optimal intermediate state where parenchymal cells are sufficiently broken down to improve strength while maintaining manufacturing efficiency. This balanced approach achieves both mechanical strength and ease of production.
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 provides a cost-effective separator with improved short-circuit resistance and impedance characteristics, suitable for low-voltage aluminum electrolytic capacitors, by reducing parenchymal cells and enhancing fiber length and density, thus preventing short circuits and maintaining capacitor performance.
Implementation Method 1
a material of the separator is required to have electrical insulation
Implementation Method 2
is required to have hydrophilicity and lipophilicity in order to retain various kinds of electrolytic solutions
Implementation Method 3
a short-circuit rate of no more than 10% when 500 V are applied during separator dielectric breakdown testing
Data Source
AI summary
A separator for an aluminum electrolytic capacitor. The separator makes it possible to use inexpensive fibers and has excellent impedance characteristics and short-circuit resistance performance. When the separator for an aluminum electrolytic capacitor is interposed between a positive electrode and a negative electrode of an aluminum electrolytic capacitor and 500 V are applied during separator dielectric breakdown testing, the separator for an aluminum electrolytic capacitor has a short-circuit rate of no more than 10%.