Electrode Insulating Composition With Wet Adhesion in Liquid Electrolyte

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Solution Overview

Problem

Conventional insulating coating layers for electrodes in secondary batteries exhibit degraded wet adhesion when immersed in a liquid electrolyte, leading to lithium ion migration and capacity expression issues, which can degrade battery safety.

Innovation Solution

An insulating composition for electrodes is developed, comprising an aqueous binder dispersed in a non-aqueous solvent and inorganic particles, with a weight ratio of inorganic particles to aqueous binder ranging from 1:99 to 95:5, enhancing wet adhesion and blocking lithium ion migration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional insulating coating layer is applied to the electrode, then electrical insulation is improved, but wet adhesion deteriorates when immersed in liquid electrolyte

Engineering Contradiction:

Improveelectrical insulationVSAvoidwet adhesion

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The insulating coating layer uses a composite material system consisting of inorganic particles (such as Al2O3, SiO2, TiO2) dispersed in a binder polymer matrix (such as PVDF, CMB). This composite structure provides both electrical insulation through the inorganic particles and maintains wet adhesion through the binder polymer's interaction with the electrode substrate, resolving the contradiction between insulation performance and adhesion stability in liquid electrolyte environments.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes parameters including the weight ratio of inorganic particles to binder polymer (typically 90:10 to 99:1), particle size distribution (0.1-10 μm), and binder content to achieve both excellent electrical insulation and stable wet adhesion. By carefully controlling these parameters, the coating maintains its integrity and adhesion strength when immersed in liquid electrolyte while providing effective insulation.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the separator is used to maintain electrical insulation, then safety is improved in normal situations, but heat resistance deteriorates at high temperatures

Engineering Contradiction:

Improveelectrical insulationVSAvoidheat resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The insulating coating is applied to modify the electrode surface properties, creating a thermal barrier that raises the effective temperature threshold for short-circuit prevention. The coating materials and their optimized compositions enable the system to maintain insulation functionality at temperatures exceeding the separator's melting point, effectively addressing the heat resistance limitation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The insulating coating acts as a pre-established protective layer on the electrode surface that cushions against thermal runaway. By providing an additional insulation barrier before thermal events occur, the coating prevents direct contact between electrodes even when the separator contracts at high temperatures, thereby compensating for the separator's heat resistance limitations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If an insulating coating layer is applied to prevent short circuit, then safety is improved, but lithium ion migration increases causing capacity expression

Engineering Contradiction:

Improveshort circuit preventionVSAvoidlithium ion migration

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The insulating coating is applied selectively to specific regions of the electrode, particularly the overlay region where short circuits are most likely to occur. This localized application provides insulation exactly where needed while leaving other regions open for normal lithium ion transport, thus preventing short circuits without blocking essential ion migration pathways.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The insulating coating employs a porous structure with controlled porosity that allows lithium ions to pass through via diffusion while maintaining electrical insulation. The porous architecture provides tortuous paths for ion transport that prevent direct electronic contact between electrodes, thereby achieving short circuit prevention without completely blocking lithium ion migration.

Inventive Principle:

Principle #31Porous materials

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 insulating composition achieves excellent wet adhesion in a liquid electrolyte, effectively blocking lithium ion migration and suppressing capacity expression, thereby enhancing the stability and safety of secondary battery cells.

Implementation Method 1

an aqueous binder dispersed in a non-aqueous solvent

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

effectively blocking lithium ion migration

Methodology Applied

Scientific EffectIon blocking:

Data Source

PatentUS20250038214A1Insulating Composition for Electrode Having Excellent Wet Adhesion and Preparation Method Thereof

Publication Date: 2025.01.30 LG ENERGY SOLUTION LTD

AI summary

An insulating composition having excellent wet adhesion and a preparation method thereof are provided. Due to the excellent wet adhesion in a liquid electrolyte, there is an advantage in that migration of lithium ions in an overlay region of an electrode can be blocked to suppress capacity expression and the like.