Separator Inorganic Coating Layer Adhesion Resistance Trade-off

Solution Overview

Problem

Conventional separators for soft pack batteries face challenges in maintaining low resistance and electrolyte absorption ratios while ensuring adequate adhesion between electrodes, which affects the cycle life and performance of the batteries.

Innovation Solution

A separator with an inorganic coating layer containing a polyvinylidene fluoride-based resin and inorganic particles, where the resin has a specific polymerization unit substitution ratio and melting point, is used to achieve low electrolyte absorption and improved adhesion, along with a porous substrate for enhanced ion conductivity and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a polyvinylidene fluoride-based resin layer is formed on a polyolefin microporous layer to improve adhesion, then adhesion between electrode and separator is improved, but resistance increases and electrolyte absorption ratio increases

Engineering Contradiction:

ImproveadhesionVSAvoidresistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by combining polyvinylidene fluoride-based resin with inorganic particles (such as metal oxides or ceramic particles) to create a coating layer that achieves both good adhesion and low resistance. The inorganic particles provide conductive pathways and prevent excessive electrolyte absorption, while the resin matrix ensures proper adhesion to the electrode.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes porous materials by controlling the pore structure of the coating layer to maintain ion permeability. The porous structure allows electrolyte penetration and ion transport while the coating provides adhesion functionality, thus balancing adhesion requirements with resistance control.

Inventive Principle:

Principle #31Porous materials

2Strength

If a polyvinylidene fluoride-based resin layer is formed on a polyolefin microporous layer to improve adhesion, then adhesion between electrode and separator is improved, but electrolyte absorption ratio increases

Engineering Contradiction:

ImproveadhesionVSAvoidelectrolyte absorption ratio

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent applies composite materials by combining polyvinylidene fluoride-based resin with inorganic particles (such as metal oxides or ceramic particles) to create a coating layer that achieves both good adhesion and low resistance. The inorganic particles provide conductive pathways and prevent excessive electrolyte absorption, while the resin matrix ensures proper adhesion to the electrode.

Inventive Principle:

Principle #40Composite materials

3Strength

If the thickness of the adhesive porous layer is increased to improve adhesion, then adhesion between electrode and separator is improved, but ion permeability decreases

Engineering Contradiction:

ImproveadhesionVSAvoidion permeability

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent utilizes porous materials by controlling the pore structure of the coating layer to maintain ion permeability. The porous structure allows electrolyte penetration and ion transport while the coating provides adhesion functionality, thus balancing adhesion requirements with resistance control.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent applies composite materials by combining polyvinylidene fluoride-based resin with inorganic particles (such as metal oxides or ceramic particles) to create a coating layer that achieves both good adhesion and low resistance. The inorganic particles provide conductive pathways and prevent excessive electrolyte absorption, while the resin matrix ensures proper adhesion to the electrode.

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 provides excellent adhesion between the separator and electrodes, maintaining low resistance and electrolyte absorption ratios, thereby improving the cycle life and performance of the batteries.

Implementation Method 1

an inorganic coating layer formed on at least one surface of the porous substrate, wherein the inorganic coating layer includes a binder resin and inorganic particles

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a porous substrate and an inorganic coating layer formed on at least one surface of the porous substrate

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11728542B2Separator for electrochemical device comprising inorganic coating layer and method for manufacturing the same

Publication Date: 2023.08.15 LG CHEM LTD

AI summary

A separator for an electrochemical device, including a porous substrate and an inorganic coating layer formed on at least one surface of the porous substrate and method for manufacturing the same are provided. The inorganic coating layer includes a binder resin and inorganic particles, and the binder resin includes a polyvinylidene fluoride-based resin and shows a low electrolyte absorption ratio. The separator has excellent adhesion with an electrode and shows low resistance characteristics.