Core-Shell Coated Battery Separator for Thermal Runaway Resistance
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Solution Overview
Problem
Conventional separators for electrochemical devices lack a sufficient heat-absorbing function, which can lead to thermal runaway and safety issues during rapid temperature increases.
Innovation Solution
A separator with a porous organic/inorganic coating layer that includes heat conductive inorganic particles and core-shell particles, where the core-shell particles have a metal hydroxide core with heat-absorbing properties and a polymer resin shell, enhancing both heat conductivity and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a porous organic/inorganic coating layer is formed on a porous polymer substrate to improve heat conductivity, then heat dissipation is enhanced, but the heat-absorbing function remains insufficient during rapid temperature increases
Solution Approach 1:
The patent applies composite materials by combining heat conductive inorganic particles (such as aluminum oxide, magnesium oxide, or boron nitride) with heat-absorbing organic particles (such as polyethylene or polypropylene) in a coating layer on the porous polymer substrate. This composite structure enables the separator to simultaneously achieve high heat conductivity for rapid heat dissipation and high heat-absorbing capacity through the phase change of organic particles, resolving the contradiction between heat conductivity and heat-absorbing function.
2Ease of manufacture
If conventional polyolefin-based porous substrates are used as separators, then manufacturing is simple and cost-effective, but severe heat shrinking occurs at temperatures of 100°C or higher causing short-circuit
Solution Approach 1:
The patent changes the thermal parameters of the separator by incorporating inorganic particles with high heat resistance (such as aluminum oxide, magnesium oxide, boron nitride) into the coating layer. These inorganic particles maintain structural stability at temperatures above 100°C, preventing the heat shrinkage that occurs in conventional polyolefin substrates, while the overall manufacturing process remains relatively simple and cost-effective.
3Temperature
If inorganic particles are coated with excessive binder polymer to form a porous organic/inorganic coating layer, then heat conductivity is improved, but heat absorption capacity is reduced
Solution Approach 1:
The patent applies local quality by creating a coating layer with heterogeneous composition where heat conductive inorganic particles and heat-absorbing organic particles are distributed throughout the binder polymer matrix. This local distribution allows different regions of the coating layer to perform different functions: inorganic particles provide heat conductivity pathways, while organic particles provide heat absorption capacity through their phase change properties, thereby resolving the contradiction between heat conductivity and heat absorption capacity.
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 proposed separator effectively disperses heat generated in the battery, absorbs heat rapidly, and improves safety by preventing thermal runaway, while maintaining battery performance and energy density.
Implementation Method 1
a porous organic/inorganic coating layer which includes a heat conductive inorganic particle
Implementation Method 2
the core-shell particles have a metal hydroxide core with heat-absorbing properties
Data Source
AI summary
Provided is a separator for an electrochemical device, including: a porous polymer substrate; and a porous organic/inorganic coating layer formed on at least one surface of the porous polymer substrate and including heat conductive inorganic particles and core-shell particles, wherein the particles are bound to one another by a binder polymer, and wherein the core-shell particle includes a core portion and a shell portion surrounding the surface of the core portion, the core portion includes a metal hydroxide having heat-absorbing property at 150-400° C. or an organic particle having a glass transition temperature, the shell portion includes a polymer resin, and the polymer resin is a water-insoluble polymer or crosslinked polymer. An electrochemical device including the separator is also provided. It is possible to provide a separator with an improved heat-absorbing effect and safety, and an electrochemical device including the same.