Heat Fusion Separator Coating for Thermal Stability and Adhesion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current separators for electrochemical devices face issues with thermal stability and adhesive strength to electrodes, leading to potential internal short circuits and safety concerns due to heat shrinkage and lack of adhesiveness, which can result in fires during high-temperature operations.

Innovation Solution

A separator with an inorganic particle layer and a heat fusion layer on a porous substrate, where the heat fusion layer has a surface gloss value of 10 GU or more, providing enhanced thermal stability and adhesive strength, and a hydrolytic condensate of a silane compound is used as a binder to improve the density and uniformity of the inorganic particle layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If an organic-inorganic composite porous separator with an inorganic particle layer stacked on a porous substrate is used to improve thermal stability, then heat shrinkage rate is reduced to some degree, but the separator still lacks sufficient thermal stability and adhesive strength to the electrode

Engineering Contradiction:
Improvethermal stabilityVSAvoidadhesive strength to electrode
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent applies composite materials by combining organic porous substrate with inorganic particles (such as metal oxides or ceramic particles) to create an organic-inorganic composite separator. This composite structure leverages the thermal stability of inorganic materials while maintaining the porosity and flexibility of organic substrates, thereby simultaneously improving both thermal stability and adhesive strength properties

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs parameter changes by modifying the surface properties of the separator through treatments such as plasma treatment, corona discharge, or chemical grafting. These treatments alter surface energy, roughness, and chemical composition parameters to enhance adhesive strength between the separator and electrode while preserving thermal stability characteristics

Inventive Principle:
Principle #35Parameter changes

2Strength

If the separator lacks sufficient adhesive strength to the electrode, then a lifting phenomenon occurs between the electrode and separator during charging and discharging, but this leads to short circuit between electrodes and safety concerns

Engineering Contradiction:
Improveadhesive strengthVSAvoidbattery stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by pre-treating the separator surface with adhesive promoters or coating layers before battery assembly. This preparatory measure ensures strong initial bonding between separator and electrode, preventing the lifting phenomenon that could lead to short circuits and safety issues during subsequent charging and discharging cycles

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent utilizes parameter changes by adjusting surface energy and chemical composition of the separator through various treatments to optimize adhesive strength. By modifying these surface parameters, the separator maintains reliable contact with electrodes under thermal and mechanical stress, preventing lifting and ensuring battery stability

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the separator causes internal short circuit due to shrinkage at high temperature, then fire risk increases, but improving thermal stability requires additional inorganic layers that may reduce air permeability

Engineering Contradiction:
Improvethermal stabilityVSAvoidair permeability
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent applies porous materials by incorporating porous inorganic particles or creating a porous structure within the inorganic particle layer. This porous configuration allows the separator to maintain high air permeability for efficient ion transport while the inorganic framework provides thermal stability and prevents shrinkage-induced short circuits at elevated temperatures

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent employs composite materials with carefully controlled porosity and interconnected pore structures. The composite design ensures that inorganic components provide thermal stability without densely packing the structure, thereby maintaining adequate air permeability for battery operation while preventing high-temperature shrinkage and short circuits

Inventive Principle:
Principle #40Composite 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 solution significantly improves thermal stability, adhesive strength, and air permeability, ensuring the separator maintains integrity and functionality at high temperatures, reducing the risk of short circuits and enhancing the safety and performance of electrochemical devices.

Implementation Method 1

a heat fusion layer provided on at least one surface of the inorganic particle layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

significantly improved high heat resistance

Methodology Applied
Scientific EffectThermal stability: Thermal Insulation

Data Source

PatentUS11811090B1Separator, method of manufacturing separator, and electrochemical device including separator
Publication Date: 2023.11.07 SK INNOVATION CO LTD

AI summary

The present invention relates to a separator, a method of manufacturing the separator, and an electrochemical device including the separator. An embodiment of the present invention may provide a separator including: a porous substrate; an inorganic particle layer provided on at least one surface of the porous substrate; and a heat fusion layer provided on at least one surface of the inorganic particle layer, wherein a surface gloss value at 60° C. of a surface of the heat fusion layer is 10 GU or more.