Separator Coating Slurry for Battery Safety
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Solution Overview
Problem
Commercial polyolefin-based separators for electrochemical devices have poor wetting characteristics, adhesive properties, and low melting temperatures, leading to low electrolyte uptake, poor conductivity, and mechanical instability, particularly at high temperatures, which affects the performance and safety of electrochemical devices.
Innovation Solution
A coating slurry comprising a polymer with an intrinsic viscosity ranging from 0.5 to 3.0 mL/g, an inorganic filler, and a solvent is applied to a porous base membrane, forming a coating layer that enhances adhesion, heat resistance, and porosity, thereby improving the mechanical strength and cycle life of the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polyolefin-based separator is used, then cost is reduced and chemical stability is improved, but wetting characteristics deteriorate and adhesive property deteriorates
Solution Approach 1:
The patent applies composite materials by forming a coating layer comprising both adhesive polymer and inorganic particles on the polyolefin microporous membrane. This composite structure combines the cost advantages and chemical stability of polyolefin with the improved wetting and adhesion properties of the coating layer, resolving the contradiction between low cost and poor wetting characteristics.
2Stability of the object's composition
If a polyolefin-based separator is used, then chemical stability is improved, but adhesive property deteriorates
Solution Approach 1:
The patent segments the separator into two functional parts: a polyolefin microporous membrane base layer that provides chemical stability, and a separate coating layer comprising adhesive polymer and inorganic particles that provides adhesive property. This segmentation allows each layer to independently fulfill its specific function without compromising the other.
3Ease of manufacture
If a polyolefin-based separator is used, then low cost is achieved, but melting temperature is reduced
Solution Approach 1:
The patent applies local quality by creating a coating layer with different thermal properties on the polyolefin membrane surface. The coating layer comprising adhesive polymer and inorganic particles provides localized high-temperature stability at the critical interface regions, while the bulk polyolefin membrane maintains its cost advantage and inherent chemical stability.
4Strength
If a coating layer is formed on polyolefin membrane, then adhesive property is improved, but device complexity increases
Solution Approach 1:
The patent uses porous materials by forming a porous coating layer comprising adhesive polymer and inorganic particles on the microporous polyolefin membrane. The porous structure of the coating layer maintains compatibility with the electrolyte and facilitates ion transport while providing the necessary adhesive property, achieving functional improvement without excessive structural complexity.
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 coated separator exhibits improved adhesive properties, mechanical strength, and cycle performance, ensuring low internal resistance and enhanced safety for electrochemical devices, particularly in high-energy density and high-power density applications.
Implementation Method 1
removing the at least one solvent from the wet coating layer to form a coating layer
Data Source
AI summary
Disclosed are a coating slurry for preparing a separator for an electrochemical device, comprising at least one polymer having an intrinsic viscosity ranging from 0.5 to 3.0 mL/g, at least one inorganic filler, and at least one solvent; a method for preparing the coating slurry; and a method for preparing a separator for an electrochemical device using the coating slurry; as well as a separator and an electrochemical device comprising the separator.