Separator Pore Control via Inorganic Particle Filling
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Solution Overview
Problem
Conventional non-woven fabric separators in electrochemical devices have weak mechanical strength and large pores, leading to potential rupture and leak currents, compromising safety and insulating properties.
Innovation Solution
A method to prepare a separator by filling micro-sized pores in a non-woven fabric substrate with inorganic particles and a polymer binder, controlling the pore size to the nanometer scale, enhancing mechanical strength and preventing leak currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a porous non-woven substrate is used as a separator, then cost efficiency is improved, but mechanical strength deteriorates and the substrate is apt to rupture
Solution Approach 1:
The patent uses a composite structure consisting of a non-woven fabric substrate combined with a porous coating layer containing inorganic particles and binder. This composite approach allows the base fabric to provide mechanical support while the coating layer provides the required pore structure for ion transport, resolving the contradiction between mechanical strength and porosity requirements.
Solution Approach 2:
The patent applies porous materials in the form of a coating layer with controlled porosity (30-70%) on the non-woven fabric substrate. This porous coating provides the necessary ion transport pathways while the underlying fabric maintains mechanical integrity, allowing both cost efficiency and mechanical strength to be achieved.
2Ease of manufacture
If a porous non-woven substrate is used as a separator, then cost efficiency is improved, but insulating property deteriorates due to leak current
Solution Approach 1:
The patent controls the pore size parameters within specific ranges (average pore size 0.5-5 μm, porosity 30-70%) to optimize both insulating properties and ion transport. By carefully adjusting these parameters, the separator achieves sufficient electrical insulation while maintaining cost efficiency through the use of non-woven fabric substrate.
Solution Approach 2:
The patent applies different properties to different parts of the separator structure: the non-woven fabric substrate provides mechanical support and basic insulation, while the porous coating layer provides controlled ion transport pathways. This local differentiation of properties allows the separator to simultaneously achieve good insulating characteristics and cost efficiency.
3Reliability
If inorganic particles and polymer binder are introduced into micro-sized pores, then pore size is controlled to nanometer scale and leak current is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the pore-size control function from the bulk substrate structure and implements it in a separate porous coating layer. This allows the underlying non-woven fabric to maintain its simple, cost-effective structure while the coating layer provides the refined nanometer-scale pore control needed to prevent leak current, thus managing manufacturing complexity.
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 method effectively increases the mechanical strength of the separator and prevents insulating property deterioration by controlling pore size, ensuring safer and more reliable electrochemical device operation.
Implementation Method 1
filling the micro-sized pores of the substrate with inorganic particles and a polymer binder
Implementation Method 2
the inorganic particles are positioned in gaps of the polymer fibers and adhered thereto by the polymer binder
Data Source
Figure 1
AI summary
The present invention refers to a method of preparing a separator, comprising: producing a dispersion comprising inorganic particles, a polymer binder, polymer fibers and a solvent; applying the dispersion on the top surface of a substrate to form a non-woven fabric web as a layer comprising the inorganic particles, the polymer binder and the polymer fiber, in which the inorganic particles are positioned in gaps of the polymer fibers and adhered thereto by the polymer binder; and drying and compressing the non-woven fabric web to obtain a non-woven fabric substrate; a separator prepared by the method; and an electrochemical device comprising the separator. In the method of the present invention, micro-sized pores present in a conventional non-woven fabric substrate are sufficiently filled with inorganic particles and a polymer binder to control the pore size on a nanometer scale, thereby inhibiting the generation of a leak current and thus preventing the insulating property of electrochemical devices using the separator from being deteriorated. Also, the filling of the inorganic particles in the pores of the non-woven fabric substrate made of polymer fibers can increase the mechanical strength of the separator.