Composite Separator Coating Slurry Dispersibility
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Solution Overview
Problem
Inorganic particles in slurry for electrochemical devices tend to sink prematurely due to insufficient dispersibility, leading to reduced adhesive strength and impaired battery performance.
Innovation Solution
A slurry with inorganic particles of 0.01 μm to 15 μm diameter and a viscosity adjusted using the equation η≥40 d2, containing 10 to 50 parts by weight of inorganic particles and 1 to 10 parts by weight of organic binder polymer per 100 parts by weight of solvent, enhancing dispersibility and preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of inorganic particles is included in the slurry to improve battery performance, then the functional effect is enhanced, but the inorganic particles sink prematurely due to insufficient dispersibility
Solution Approach 1:
The patent changes the particle diameter parameter of inorganic particles to a specific range (0.01 μm to 15 μm) and adjusts the viscosity parameter of the slurry to a predetermined range based on particle diameter. These parameter changes optimize the balance between particle loading amount and dispersibility, preventing premature sinking while maintaining high inorganic particle content for improved battery performance.
2Stability of the object's composition
If surfactant is used as dispersant to improve dispersibility of inorganic particles, then the dispersion stability is improved, but the amount of inorganic particles that can be included in the slurry relatively reduces
Solution Approach 1:
Instead of relying on surfactants, the patent changes the physical parameters of the inorganic particles themselves by controlling their diameter within a specific range (0.01 μm to 15 μm). This parameter change enables improved dispersibility and higher inorganic particle content without requiring surfactants, thus avoiding the trade-off between dispersion stability and particle loading amount.
3Stability of the object's composition
If the viscosity of the slurry is increased to improve dispersibility and prevent sinking, then the dispersion stability is improved, but the slurry becomes harder to apply to the substrate
Solution Approach 1:
The patent optimizes the viscosity parameter of the slurry to a predetermined range that is specifically correlated with the particle diameter of inorganic particles. This controlled parameter change ensures the slurry has sufficient viscosity to prevent particle sinking and maintain dispersion stability, while remaining within operable limits for easy application to substrates.
4Ease of manufacture
If inorganic particles are not dispersed uniformly in the slurry, then the manufacturing process is simpler, but the adhesive strength between inorganic particles and substrate reduces and separation occurs during battery operation
Solution Approach 1:
The patent implements parameter changes in the form of controlling inorganic particle diameter (0.01 μm to 15 μm) and adjusting slurry viscosity to a predetermined range. These changes enable uniform dispersion of inorganic particles in the slurry without complicating the manufacturing process, ensuring strong adhesive strength between particles and substrate while preventing separation during battery charging and discharging operations.
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 improved dispersibility and viscosity range allow for effective use of a larger amount of inorganic particles, reducing sinking rates and maintaining battery performance by preventing separation between inorganic particles and the substrate.
Implementation Method 1
the slurry has a viscosity of which a lower bound is a value obtained from the following Equation based on the diameter of the inorganic particles
Implementation Method 2
improved dispersibility of inorganic particles by controlling a particle diameter of an inorganic matter in the slurry
Implementation Method 3
the inorganic particles with the aim to intercalcate/deintercalate a lithium ion
Implementation Method 4
as charging and discharging of the battery proceeds
Data Source
AI summary
The present disclosure relates to an invention directed to a composite separator having a porous coating layer, where the porous coating layer is prepared from a slurry by adjusting a particle diameter of an inorganic matter that is an ingredient of the slurry, so that a sinking rate of the inorganic particles may remarkably slow down and dispersibility may be dramatically improved, and as a result, the content of the inorganic particles may relatively increase and the inorganic particles may be uniformly distributed in the coating layer on a substrate, thereby preventing a reduction in battery performance.