Electrospun Microfiber Separator for Battery Thermal Stability
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Solution Overview
Problem
Conventional secondary battery separators lack heat-resistance and uniform porosity, leading to thermal shrinkage and potential short circuits during high-temperature conditions, which compromises battery stability and efficiency.
Innovation Solution
A microfiber non-woven web with high heat-resistance, manufactured through electrospinning of engineering plastic resins like polyamideimide and polyimide, which provides excellent tensile strength and minimal shrinkage, combined with a porous polyolefin substrate and optional organic/inorganic coating for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyolefin separators are used, then the separator can be manufactured with simple process, but the separator exhibits severe thermal shrinkage at high temperature causing internal short circuit
Solution Approach 1:
The patent changes the material parameters by using engineering plastics (polyimide, polyamideimide, polyetherimide) instead of conventional polyolefin, which fundamentally alters the thermal properties and shrinkage behavior of the separator, enabling it to maintain dimensional stability at high temperatures
Solution Approach 2:
The patent creates a composite structure by combining engineering plastic fibers with polyolefin binder fibers, forming a non-woven fabric that integrates the heat-resistance of engineering plastics with the processability and shutdown function of polyolefin
2Length of moving object
If the separator is made thinner to achieve miniaturization, then the battery pack size is reduced, but the mechanical strength and heat-resistance deteriorate
Solution Approach 1:
The patent employs a thin film non-woven fabric structure made of electrospun microfibers that provides high mechanical strength and heat-resistance despite the reduced thickness, enabling both miniaturization and maintained performance
Solution Approach 2:
The patent changes the fiber material from conventional polyolefin to engineering plastics, which fundamentally improves the strength-to-thickness ratio and thermal stability, allowing the separator to be made thinner without sacrificing mechanical properties or heat-resistance
3Manufacturing precision
If the separator is made of single-layer structure, then the manufacturing process is simple, but the porosity uniformity and charging/discharging efficiency are insufficient
Solution Approach 1:
The patent segments the separator into functional zones with different fiber compositions and porosity characteristics, creating regions optimized for different functions such as electrolyte retention, ion transport, and mechanical support, thereby achieving uniform porosity and high efficiency
Solution Approach 2:
The patent applies local quality by varying the fiber composition, diameter, and distribution in different regions of the separator to optimize local functions, resulting in improved porosity uniformity and charging/discharging efficiency throughout the entire separator
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 separator with improved heat-shrinkage resistance, high air permeability, and efficient charging/discharging characteristics, minimizing the risk of short circuits and enhancing the stability and efficiency of secondary batteries, even under high-temperature conditions.
Implementation Method 1
a microfiber non-woven web obtained by electrospinning an engineering plastic resin solution
Data Source
AI summary
The present disclosure provides a method for manufacturing an electrospun microfiber non-woven web with high strength for a lithium secondary battery, a non-woven web manufactured therefrom, and a separator comprising the non-woven web. More specifically, the present disclosure provides a microfiber non-woven web manufactured by bringing a solution of engineering plastic resin with high heat-resistance into electrospinning, the manufacture thereof, and a separator comprising the web.According to the present disclosure, the engineering plastic resin with high heat-resistance is used in the manufacture of the microfiber non-woven web to provide improved physical properties including tensile strength and good heat-resistance and chemical-resistance, as compared with conventional polyethylene-based separators.