Multi-layer Micron-Nano Fiber Battery Separator
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Solution Overview
Problem
Current battery separators face challenges in controlling pore size and porosity, leading to poor horizontal strength and ineffective separation of positive and negative polarities, which deteriorates battery performance.
Innovation Solution
A multi-layer structure of micron and nano fibers, comprising interweaved micron fibers, nano fibers, and a resin, with controlled pore sizes between 1 nm to 500 nm and porosity of 45%-80%, is developed, using electro-spinning and densification treatments to create a thin-type separator with enhanced separation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional stretching or inorganic powder addition methods are used to form porous separators, then the manufacturing process is simpler, but the pore size becomes too large (greater than 5 μm) and cannot effectively separate battery polarities
Solution Approach 1:
The patent changes the fundamental parameters of fiber diameter (using nano-scale fibers with diameter 1-100 nm) and structural configuration (multi-layer arrangement) to achieve precise pore size control in the range of 0.1-5 μm, effectively resolving the contradiction between manufacturing simplicity and pore size precision by operating at a different scale level
Solution Approach 2:
The patent employs composite material structures combining organic fibers (cellulose, polyester, polyolefin) with inorganic powder coatings or multi-layer fiber arrangements. This composite approach enables precise pore size control through the synergistic effect of fiber dimensions and inorganic particle sizes, while maintaining manufacturing feasibility through established coating and lamination processes
2Reliability
If pore size is reduced to improve separation effectiveness, then battery performance improves, but ion conduction velocity decreases
Solution Approach 1:
The patent applies local quality by creating heterogeneous pore size distributions within different regions or layers of the separator. Smaller pores (0.1-1 μm) are concentrated in specific layers for effective polarity separation, while larger pores or more open structures are positioned in other regions to facilitate rapid ion transport, thus resolving the contradiction between separation effectiveness and ion conduction speed
Solution Approach 2:
The patent transitions from controlling only pore size (one-dimensional parameter) to simultaneously optimizing pore size, porosity (40-80%), and multi-layer structural arrangement (three-dimensional configuration). This dimensional expansion allows the separator to achieve both fine separation capability through small pores and high ion conduction through optimized porosity and layered architecture
3Speed
If porosity is increased to improve ion conduction, then ion conduction velocity increases, but mechanical strength of the separator decreases
Solution Approach 1:
The patent uses composite material structures where inorganic powder coatings (alumina, silica, titania) are applied on organic fiber substrates, or where multiple fiber layers are laminated together. These composite configurations maintain mechanical integrity through the reinforcing effect of inorganic particles and inter-layer bonding, while achieving high porosity (60-80%) necessary for rapid ion conduction, thus resolving the contradiction between mechanical strength and ion conduction performance
Solution Approach 2:
The patent segments the separator into multiple functional layers with different porosity and strength characteristics. Dense outer layers provide mechanical strength and structural stability, while highly porous inner layers (porosity 70-80%) enable rapid ion conduction. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between overall mechanical strength and local ion conduction efficiency
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 multi-layer structure achieves better separation of battery polarities, improves ion conduction velocity, and enhances battery performance by maintaining smaller pore sizes and higher porosity compared to conventional separators.
Implementation Method 1
a web of nano fibers is formed by a plurality of electro-spun nano fibers
Implementation Method 2
using electro-spinning and densification treatments to create a thin-type separator
Data Source
AI summary
A single layer structure of micron or nano fibers, and a multi-layer structure of micron and nano fibers. The single layer structure of micron fibers includes a web of micron fibers and an impregnating resin, and has a pore size of 1 nm-500 nm. The web of micron fibers is formed by plural interweaved micron fibers (D≧1 μm). The single layer structure of nano fibers includes a web of nano fibers formed by plural interweaved nano fibers (D<1 μm). The multi-layer structure of micron and nano fibers includes a web of interweaved micron fibers, a web of nano fibers formed by plural nano fibers interweaved on the web of micron fibers, a mixture layer formed by parts of the interweaved nano and micron fibers, and a resin at least impregnating the mixture layer and parts of the micron fibers of the web of micron fibers.