Solid Electrolytic Capacitor Separator with Mixed Fiber Composition
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Solution Overview
Problem
The existing methods for forming solid electrolytic capacitors using conductive polymers face challenges in achieving a dense solid electrolyte layer due to reduced holding power of the separator paper during carbonization, leading to deteriorated ESR characteristics, especially when using polythiophene or its derivatives.
Innovation Solution
A solid electrolytic capacitor design that uses a separator paper mixed with low heat resistance fibers and high heat resistance fibers, where the high heat resistance fibers are not carbonized, maintaining narrow spaces between fibers to enhance the holding power of the mixed solution and facilitate the formation of a dense solid electrolyte layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separator paper is carbonized to increase voids and improve solution penetration, then manufacturing precision of solid electrolyte layer is improved, but holding power of separator paper is reduced leading to deteriorated ESR characteristic
Solution Approach 1:
The separator paper is constructed as a composite material containing both carbonizable fibers (cellulose) and non-carbonizable synthetic fibers (polyester, polyamide, acrylic). This composite structure allows partial carbonization to create voids for solution penetration while the synthetic fibers maintain structural integrity and holding power, resolving the contradiction between manufacturing precision and reliability
Solution Approach 2:
Different regions of the separator paper have different properties: cellulose fibers provide carbonization capability in specific areas to create voids, while synthetic fibers provide structural support in other areas to maintain holding power. This local differentiation allows simultaneous achievement of good solution penetration and maintained ESR characteristic
2Ease of manufacture
If separator paper density is reduced to facilitate mixed solution penetration, then ease of manufacture is improved, but holding power is reduced causing poor solid electrolyte layer formation
Solution Approach 1:
The composite separator paper combines cellulose fibers (which can be carbonized to create voids) with synthetic fibers (which maintain structural integrity). This allows the separator to have reduced density for easy solution penetration while maintaining sufficient holding power through the synthetic fiber network, resolving the contradiction between ease of manufacture and manufacturing precision
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
This approach allows for the formation of a dense solid electrolyte layer, significantly improving the ESR characteristic by maintaining the holding power of the mixed solution and reducing voids in the separator paper during carbonization.
Implementation Method 1
the wound element (21) is heated to elevated temperatures of about 150 to 300° C. to be carbonized after being wound into a roll
Data Source
AI summary
A solid electrolytic capacitor (1) is prepared by carbonizing a wound element (21) formed by winding an anode foil (22) and a cathode foil (23) together with a separator paper (4) sandwiched therebetween, and forming a solid electrolyte layer, including said separator (4), including a conductive polymer between the anode foil (22) and the cathode foil (23). The separator paper (4) is paper prepared by mixing fibers having low heat resistance and carbonized by said carbonizing, and fibers having high heat resistance not carbonized by said carbonizing, and fibrillated fibers having narrow spaces between fibers are used as said fibers having high heat resistance. The solid electrolytic capacitor has an excellent ESR characteristic, in which a dense solid electrolyte layer can be formed by a chemical polymerization method.