Crimped Composite Non-Woven Support for Thin Solid Electrolyte Sheets
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Solution Overview
Problem
Existing non-woven fabrics for supporting solid electrolytes in all-solid-state lithium batteries suffer from low tensile strength, poor process performance, difficulty in thorough filling with electrolyte, high moisture absorption leading to decreased productivity, and issues with cracking and hole defects, which hinder the production of thin, self-sustainable electrolyte sheets.
Innovation Solution
A non-woven fabric containing heat-fusible composite fibers with crimps, specifically core-sheath type fibers with polypropylene-based core and polyolefin-based sheath, and optionally laminated with nanofiber layers, enhances tensile strength, facilitates complete electrolyte filling, and reduces cracking and hole defects, enabling the production of thin, flexible solid electrolyte sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PET non-woven fabric is used as support base material, then the non-woven fabric can be filled with solid electrolyte, but the tensile strength becomes extremely low resulting in unsatisfactory process performance
Solution Approach 1:
The invention uses composite non-woven fabric made by combining PET fibers with heat-resistant fibers (such as polyimide or aramid fibers). This composite structure maintains the good filling capability of PET while adding the high temperature resistance and strength of heat-resistant fibers, resolving the contradiction between filling capability and tensile strength.
2Reliability
If PET non-woven fabric is used as support, then the non-woven fabric can be filled with solid electrolyte, but moisture absorption increases leading to decreased productivity
Solution Approach 1:
By compositeing PET fibers with hydrophobic heat-resistant fibers (such as polyimide or aramid), the resulting non-woven fabric maintains the filling capability of PET while significantly reducing moisture absorption due to the hydrophobic nature of heat-resistant fibers, thereby improving productivity.
3Length of moving object
If the non-woven fabric is pressed into a thin film, then the solid electrolyte layer can be thinned, but cracks originating from fibers are prone to be created
Solution Approach 1:
The heat-resistant fibers in the composite non-woven fabric have high strength and flexibility, which prevent fiber breakage during thinning processes. This allows the solid electrolyte layer to be thinned effectively while maintaining crack resistance, as the heat-resistant fiber network provides structural integrity even at reduced thickness.
Solution Approach 2:
The invention changes the fiber composition parameters by introducing heat-resistant fibers with different mechanical properties than PET. These fibers have higher elongation at break and strength, which fundamentally alters the non-woven fabric's behavior during thinning, preventing crack formation while enabling reduced thickness.
4Weight of stationary object
If extremely low basis weight non-woven fabric is produced by wet paper making, then the non-woven fabric can be formed into sheet, but constituent fibers may be caught on paper making wire or blanket creating hole defects
Solution Approach 1:
The heat-resistant fibers in the composite non-woven fabric have higher stiffness and dimensional stability than PET fibers. This prevents fibers from being caught on the paper making wire or blanket during wet paper making, even at extremely low basis weights, thereby eliminating hole defects while maintaining low weight.
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 proposed non-woven fabric ensures excellent process performance, complete electrolyte filling, and minimizes defects, resulting in a self-sustainable and flexible solid electrolyte sheet suitable for thin film applications.
Implementation Method 1
heat-fusible composite fibers with a crimp are contained in an amount of not less than 60 mass % and not more than 100 mass % and are heat-fused
Data Source
AI summary
The present invention provides a non-woven fabric for supporting a solid electrolyte in which heat-fusible composite fibers with a crimp are contained in an amount of not less than 60 mass % and not more than 100 mass % and are heat-fused, and a solid electrolyte sheet. The non-woven fabric for supporting a solid electrolyte is excellent in process performance, is satisfactorily filled with a solid electrolyte, is suitable for achieving a thin solid electrolyte sheet, and has few hole defects. The solid electrolyte sheet is excellent in self-sustainability and flexibility.