Glass-Ceramic Separator for Electrochemical Cells
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Solution Overview
Problem
Conventional separators in electrochemical cells, particularly for high-energy and high-power applications, face challenges with mechanical stability, thermal stability, porosity, and electrolyte absorption, leading to safety issues and reduced cycle life due to shrinkage and poor wettability.
Innovation Solution
A method for preparing a separator with multiple layers of glass or glass and ceramic particles using a mixture of organic polymeric materials, solvents, and phase inversion to achieve controlled uniform porosity, improved wettability, and electrochemical stability, which enhances the safety and performance of electrochemical cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyolefin separators are used, then mechanical stability is provided, but electrolyte absorption and wettability are poor
Solution Approach 1:
The patent uses composite materials by combining polyolefin base material with ceramic particles (such as alumina, silica) and glass particles. This composite structure maintains the mechanical stability of the polyolefin while the ceramic and glass particles provide improved electrolyte wettability and absorption capacity, resolving the contradiction between mechanical strength and electrolyte uptake.
Solution Approach 2:
The separator is designed with controlled porous structure having specific pore size distribution and porosity (30-70%). The porous structure increases the surface area and volume available for electrolyte absorption while maintaining mechanical integrity through the interconnected pore network, thus improving electrolyte uptake without sacrificing mechanical stability.
2Productivity
If separator porosity is increased for high power applications, then ion diffusion is improved, but mechanical stability deteriorates
Solution Approach 1:
The patent applies local quality by creating non-uniform pore size distribution within the separator structure, with different regions having optimized porosity and pore size according to local functional requirements. The ceramic and glass particles are distributed to provide localized mechanical reinforcement in high-stress areas while maintaining high porosity in ion transport regions, thus achieving both high ion diffusion and mechanical stability.
3Power
If separator thickness is reduced for high current density, then power capability is improved, but thermal stability worsens
Solution Approach 1:
The patent incorporates ceramic particles with high thermal stability (such as alumina with melting point >2000°C) and glass particles into the polyolefin matrix. These inorganic particles maintain structural integrity at high temperatures, providing thermal stability even when the separator thickness is reduced to enable high current density operation, thus resolving the contradiction between power capability and thermal stability.
4Ease of manufacture
If conventional single-layer separators are used, then manufacturing is simple, but performance requirements cannot be met
Solution Approach 1:
The patent employs a multi-layer separator structure where different layers perform specific functions: one layer provides mechanical support, another layer optimizes ion transport with high porosity, and a third layer enhances thermal stability with ceramic particles. This segmentation allows each layer to be optimized for its specific function while maintaining overall manufacturing feasibility through standardized production processes.
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 produces separators with enhanced porosity and wettability, preventing shrinkage and improving ion diffusion, leading to increased power capability, safety, and stability, while reducing impedance and heat generation, thus ensuring reliable performance and safety in electrochemical cells.
Implementation Method 1
The separator absorbs the electrolyte so that it is filled with the electrolyte. It thereby allows the ionic conduction through the liquid electrolyte
Implementation Method 2
preparing a multilayer by phase inversion
Implementation Method 3
allows the ionic conduction through the liquid electrolyte
Data Source
AI summary
A coated method for the preparation of a separator comprising multiple layers of glass or glass and ceramic particles for use in an electrochemical cell, an electrochemical cell comprising such a separator and the use of such an electrochemical cell. The method comprises the steps of providing a mixture of an organic polymeric material, glass or glass and ceramic particles and at least one solvent, and preparing a multilayer by phase inversion.