Battery Separator Coating for Thin High-Voltage Stability
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Solution Overview
Problem
Electrochemical devices face challenges in maintaining high dielectric breakdown voltage and dimensional stability at high temperatures while being thinned for high capacity and output, leading to potential internal short circuits and safety risks.
Innovation Solution
A separator with an inorganic particle layer on a porous substrate, where the inorganic particles have a specific particle size distribution and are bound by a condensation-suppressed hydrolytic condensate of a silane compound, enhancing packing density and dielectric breakdown voltage, and the substrate is treated with corona or plasma discharge to introduce polar functional groups for improved adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the separator is thinned to achieve high capacity and high output, then the energy density and power density are improved, but the dielectric breakdown voltage decreases leading to deteriorated withstand voltage characteristics
Solution Approach 1:
The patent applies composite materials by forming an inorganic particle layer on the porous substrate. The inorganic particles (such as Al2O3, SiO2, TiO2, or ZrO2) create a composite structure that enhances the dielectric breakdown voltage and thermal stability while maintaining thin overall thickness, thus resolving the contradiction between thinning for high energy density and maintaining reliability for withstand voltage characteristics
Solution Approach 2:
The patent utilizes porous materials by employing a porous substrate with controlled porosity (30-80%) and pore size (0.01-10 μm). The porous structure allows the separator to maintain mechanical integrity and electrolyte penetration while being thin, and when combined with the inorganic particle layer, achieves high dielectric breakdown voltage without compromising energy density
2Productivity
If the separator is thinned to achieve high capacity and high output, then the energy density and power density are improved, but the dimensional stability at high temperature decreases causing internal short circuit risk
Solution Approach 1:
The inorganic particle layer forms a composite structure with the porous substrate that significantly improves dimensional stability at high temperatures. The inorganic particles (Al2O3, SiO2, TiO2, ZrO2) have high thermal stability and prevent the thin separator from shrinking or deforming at operating temperatures, thus resolving the contradiction between thinning for high energy density and maintaining dimensional stability for safety
Solution Approach 2:
The patent applies parameter changes by controlling the particle size distribution of inorganic particles (D50: 0.1-5 μm, (D80-D20)/D50 ratio: 0.1-2.0) and the thickness ratio of porous substrate to inorganic particle layer (0.7-0.95). These optimized parameters enable the thin separator to maintain both high energy density and excellent dimensional stability at high temperatures
3Stability of the object's composition
If an inorganic particle layer is stacked on a porous substrate to improve dimensional stability, then the thermal stability is improved, but the overall thickness increases deteriorating high capacity characteristics
Solution Approach 1:
The patent optimizes parameters by controlling the thickness of the inorganic particle layer to be very thin (0.1-5 μm) and setting the porous substrate thickness to 3-50 μm. The thickness ratio of porous substrate to inorganic particle layer is maintained at 0.7-0.95, ensuring the overall separator remains thin enough for high energy density while providing sufficient thermal stability through the inorganic particle layer
4Stability of the object's composition
If an inorganic particle layer is stacked on a porous substrate to improve dimensional stability, then the thermal stability is improved, but the overall thickness increases deteriorating high output characteristics
Solution Approach 1:
The patent controls the particle size distribution of inorganic particles (D50: 0.1-5 μm) and the layer thickness to minimize overall separator thickness. The thin inorganic particle layer (0.1-5 μm) provides thermal stability without significantly increasing overall thickness, thus maintaining high power density while improving dimensional stability for safety
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 significantly improves dielectric breakdown voltage, thermal stability, and withstand voltage characteristics, ensuring high capacity, high output, and safety by maintaining dimensional stability at elevated temperatures even with a thin separator.
Implementation Method 1
the inorganic particle layer may have a packing density of 1.3 g/(m2
Implementation Method 2
the substrate is treated with corona or plasma discharge to introduce polar functional groups for improved adhesion
Implementation Method 3
the substrate is treated with corona or plasma discharge to introduce polar functional groups for improved adhesion
Implementation Method 4
bound by a condensation-suppressed hydrolytic condensate of a silane compound
Implementation Method 5
bound by a condensation-suppressed hydrolytic condensate of a silane compound
Data Source
AI summary
Provided are a separator, a method of manufacturing the separator, and an electrochemical device including the separator. According to an exemplary embodiment of the present disclosure, a separator including: a porous substrate and an inorganic particle layer provided on at least one surface of the porous substrate may be provided, wherein a value of the following Formula (1) is 0.135 or more: BDV/t wherein BDV is a voltage (kV) when a leakage current value is 5 mA, the voltage being measured in accordance with ASTM D 149 and the leakage current value being measured under conditions of raising an applied voltage at 5 kV/10 sec after placing the separator between electrodes of a withstand voltage tester, and t is an overall average thickness (µm) of the separator.