Titanium-Coated Battery Separator for Heat and Compression Stability
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Solution Overview
Problem
Lithium-ion battery separators face challenges in maintaining mechanical performance under compressive stress and high-temperature integrity, as they deform and lose ionic conductivity due to volume expansion of electrodes and insufficient melt integrity at high temperatures.
Innovation Solution
A high thermal-stability separator is developed with a porous substrate and an inorganic layer containing inorganic particles and a binder, coated with a titanium oxide or titanium hydroxide film using chemical solution deposition, which enhances compression retention and maintains air permeability while achieving high thermal rupture temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyolefin materials (PE/PP) are used for separator, then ease of manufacture is improved, but high temperature melt integrity deteriorates
Solution Approach 1:
The patent applies composite materials by combining polyolefin base material with titanium oxide and titanium hydroxide coatings. The separator consists of a porous substrate (polyethylene or polypropylene) coated with inorganic titanium-based materials, creating a composite structure that maintains the ease of manufacturing polyolefin while adding high-temperature stability and preventing melt integrity loss above 150°C
Solution Approach 2:
The patent changes the thermal parameters of the separator by depositing titanium oxide and titanium hydroxide films that raise the thermal rupture temperature from the original polyolefin melting point (around 100-160°C) to above 170°C. The coating layer fundamentally alters the thermal behavior and melt integrity characteristics of the separator
2Strength
If separator compression resistance is strengthened, then mechanical performance is improved, but air permeability deteriorates
Solution Approach 1:
The patent applies local quality by creating a porous coating structure on the separator surface that provides compression resistance only where needed. The titanium oxide and titanium hydroxide coating forms a porous layer with controlled pore size and distribution, giving local mechanical reinforcement while preserving overall air permeability through the separator
Solution Approach 2:
The patent uses porous materials by creating a porous coating layer of titanium oxide and titanium hydroxide on the separator. The coating maintains porosity to allow ion and air passage while the porous structure provides compression resistance, achieving both improved mechanical performance and maintained air permeability
3Reliability
If inorganic layer is added to porous substrate, then high temperature melt integrity is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical reinforcement approach (adding thick structural layers) with a chemical/coating approach. Instead of mechanically building up the separator structure to improve heat resistance, a thin chemical coating of titanium oxide and titanium hydroxide is deposited on the surface, providing high-temperature stability without significantly increasing structural complexity
Solution Approach 2:
The patent uses thin films by depositing a thin coating layer of titanium oxide and titanium hydroxide on the porous substrate. The thin film structure provides high-temperature melt integrity and thermal rupture resistance while minimizing the increase in overall device complexity and thickness
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 separator exhibits over 90% compression retention and less than 35% decrease in air permeability after compression, with a thermal rupture temperature above 170°C, ensuring safety and performance during lithium-ion battery operation.
Implementation Method 1
the titanium oxide film and/or the titanium hydroxide film is/are deposited by chemical solution deposition by sequentially applying a precursor solution and a reactive solution on the porous film to make the reactive solution react with the precursor solution
Implementation Method 2
sequentially applying a precursor solution and a reactive solution on the porous film to make the reactive solution react with the precursor solution
Data Source
AI summary
A high thermal-stability separator and method for manufacturing thereof are disclosed. The high thermal-stability separator comprises a porous film and a titanium oxide or/and titanium hydroxide film, wherein the porous film comprises a porous substrate and a inorganic layer, wherein the inorganic layer comprises a plurality of inorganic particles and a binder, the inorganic layer is formed on at least one surface of the porous substrate, and the porous substrate and the inorganic layer have a plurality of interconnected porous structures; and the titanium oxide or/and titanium hydroxide film is formed on the surface and the inner walls of porous structures of the porous film. The present high thermal-stability separator can provide enhanced compression retention and excellent high temperature melt integrity, and maintain a satisfied air permeability (Gurley) after compression.