Battery Electrode Insulating Coating to Prevent Gelation
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Solution Overview
Problem
Conventional insulating layers in secondary batteries using aqueous binders face issues with degraded wet adhesion and gelation when immersed in liquid electrolytes, leading to lithium ion migration and capacity expression problems.
Innovation Solution
A method involving the application of an electrode slurry and an insulating composition using a non-aqueous solvent, with the same solvent type for both, and including inorganic particles, to form an insulating layer that enhances wet adhesion and prevents gelation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an aqueous binder is used in the insulating layer, then wet adhesion is improved, but gelation occurs when immersed in liquid electrolyte
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by using copolymers with different monomer ratios. Specifically, it employs styrene-butadiene rubber with 70-80% butadiene content or butyl rubber with 70-80% isobutylene content, which provides both excellent wet adhesion and resistance to gelation in liquid electrolyte environments.
Solution Approach 2:
The patent uses composite binder systems combining organic and inorganic components. The insulating layer comprises organic binders (styrene-butadiene rubber or butyl rubber) combined with inorganic particles (alumina, silica, or boehmite), creating a composite material that achieves both strong adhesion and gelation resistance through synergistic effects.
2Ease of manufacture
If water is used as a solvent for coating, then coating process is simplified, but moisture vulnerability causes gelation
Solution Approach 1:
The patent changes the solvent parameter from water to non-aqueous solvents. The insulating composition uses N-methyl-2-pyrrolidone (NMP) or dimethyl carbonate (DMC) as solvents, which eliminates moisture-related gelation issues while maintaining good coating processability and electrode compatibility.
3Stability of the object's composition
If conventional non-aqueous binder is used, then moisture resistance is improved, but wet adhesion deteriorates
Solution Approach 1:
The patent uses composite binder systems combining organic and inorganic components. The insulating layer comprises organic binders (styrene-butadiene rubber or butyl rubber) combined with inorganic particles (alumina, silica, or boehmite), creating a composite material that achieves both strong adhesion and gelation resistance through synergistic effects.
Solution Approach 2:
The patent changes the chemical composition parameters of the binder by using copolymers with different monomer ratios. Specifically, it employs styrene-butadiene rubber with 70-80% butadiene content or butyl rubber with 70-80% isobutylene content, which provides both excellent wet adhesion and resistance to gelation in liquid electrolyte environments.
4Reliability
If insulating layer is applied to prevent short circuit, then safety is improved, but lithium ion migration is blocked causing capacity loss
Solution Approach 1:
The patent applies the insulating layer selectively only at the boundary region between the current collector and electrode active material, rather than covering the entire electrode surface. This localized application maintains safety by preventing short circuits at the critical boundary while preserving lithium ion migration pathways in the active material regions.
Solution Approach 2:
The patent uses a thin insulating layer with controlled thickness (1-10 μm) that provides sufficient insulation to prevent short circuits while being thin enough to allow lithium ion migration. The layer is applied partially only where needed at the boundary, avoiding excessive coverage that would block ion transport.
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 improves wet adhesion and prevents gelation, increasing electrode productivity and enhancing the stability and safety of secondary batteries by blocking lithium ion migration.
Implementation Method 1
an insulating composition including an aqueous binder substituted with a non-aqueous solvent
Implementation Method 2
does not block the migration of lithium ions in the overlay region of an electrode to cause capacity expression
Implementation Method 3
the resulting insulating layer exhibits degraded adhesion (hereinafter, referred to as wet adhesion) while being immersed in a liquid electrolyte
Data Source
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AI summary
The present technology relates to a method of manufacturing an electrode for a secondary battery, and since an electrode is manufactured using an insulating composition including an aqueous binder substituted with a non-aqueous organic solvent, the wet adhesion of an insulating layer can be increased, and the gelation between an electrode slurry and the insulating composition, which is caused by using different types of binders, can also be prevented.