UV Cured Ceramic Battery Separator for Thermal Runaway
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Solution Overview
Problem
Conventional lithium secondary battery separators made from thermoplastic polypropylene (PP) or polyethylene (PE) are mechanically weak and lack heat resistance, leading to potential fires due to melting or decomposition under high temperatures, which can cause electrical short circuits and thermal runaway.
Innovation Solution
A UV or EB curable binder is used to bind ceramic particles together to form a porous, electrically insulating separator that maintains mechanical strength and heat resistance, even at elevated temperatures, by creating a ceramic particulate-based coating that suppresses ionic flow and prevents electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic polypropylene or polyethylene is used as separator material, then the separator can be manufactured easily and costs are reduced, but the mechanical strength and heat resistance deteriorate, leading to potential fires under high temperatures
Solution Approach 1:
The patent uses a composite material consisting of inorganic ceramic particles (such as aluminum oxide, aluminum hydroxide, or magnesium hydroxide) dispersed in a polymer matrix. This composite structure combines the ease of processing thermoplastics with the high temperature stability and mechanical strength of ceramic particles, resolving the contradiction between manufacturability and thermal-mechanical performance
Solution Approach 2:
The patent changes the material parameters by incorporating ceramic particles with specific properties (high melting point, thermal stability) into the polymer matrix. This parameter change transforms the separator from a purely organic thermoplastic material to a hybrid material that maintains processability while achieving superior heat resistance and mechanical strength at elevated temperatures
2Reliability
If the separator is made thin and porous to maximize ionic flow, then the ionic conductivity is improved, but the mechanical strength and thermal stability deteriorate, increasing fire risk
Solution Approach 1:
The patent employs a porous ceramic-polymer composite structure where the ceramic particles form a rigid skeletal framework that maintains structural integrity. The porosity is controlled to allow ionic flow while the ceramic network provides mechanical support and thermal stability, enabling thin separator design without sacrificing strength or heat resistance
Solution Approach 2:
The composite structure of ceramic particles embedded in the polymer matrix creates a rigid yet porous architecture. The ceramic phase provides structural reinforcement that allows the separator to be made thinner and more porous for improved ionic conductivity while maintaining adequate mechanical strength and thermal stability
3Device complexity
If conventional thermoplastic separators are used, then the manufacturing process is simple, but the separators melt or decompose under high temperatures causing electrical short circuits and thermal runaway
Solution Approach 1:
The patent fundamentally changes the thermal parameters of the separator by incorporating ceramic particles with high melting points (aluminum oxide: 2072°C, aluminum hydroxide: decomposes at 370°C releasing water, magnesium hydroxide: decomposes at 350°C releasing water). This parameter change ensures the separator maintains structural integrity at battery operating temperatures and during thermal abuse conditions, preventing melt-through and electrical short circuits
Solution Approach 2:
The patent converts the potential harm of high-temperature decomposition into a beneficial safety feature. The ceramic particles, particularly aluminum hydroxide and magnesium hydroxide, decompose endothermically at elevated temperatures, absorbing heat and releasing water vapor that suppresses thermal runaway. This transforms the degradation process from a harmful event into a protective mechanism
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 ceramic-coated separator enhances the safety and operational stability of lithium-ion batteries by maintaining structural integrity and preventing thermal runaway, reducing the risk of fires and electrical shorts, while allowing for efficient heat dissipation.
Implementation Method 1
UV or EB cured polymer-bonded ceramic particle lithium secondary battery separators
Implementation Method 2
UV or EB cured polymer-bonded ceramic particle lithium secondary battery separators
Implementation Method 3
bind ceramic particles together to form a porous, electrically non-conductive separator
Implementation Method 4
allowing for efficient heat dissipation
Data Source
AI summary
Porous, electrically insulating, and electrochemically resistant surface coatings that strengthen and protect separators and that improve the operational safety of electrochemical devices using such separators, porous, electrically insulating, and electrochemically resistant standalone separators, the use of ultraviolet (UV) or electron beam (EB) curable binders to secure an electrically insulating, porous, ceramic particle coating on separators or to produce standalone separators, and methods of producing polymer-bound ceramic particle separator coatings, separators and electrochemical devices by UV or EB curing slurries of reactive liquid resins and ceramic particles.