Composite-Coated Battery Separator for Heat Resistance and Wettability

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving high heat resistance and mechanical strength while maintaining excellent wettability by an organic electrolytic solution, as thinner separators lead to stability issues and inorganic oxide coatings can clog pores, impairing lithium-ion pathways.

Innovation Solution

A separator with a web structure of organic fibers and a composite coating layer comprising heat-resistant inorganic particles and a hydrophilic organic compound, formed through vapor-deposition and atomic layer deposition, which enhances heat resistance and electrolyte-impregnation properties without increasing thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the thickness of the separator is decreased to increase loading amounts of electrodes, then the energy density is improved, but the heat resistance and mechanical strength deteriorate

Engineering Contradiction:

Improveloading amount of electrodesVSAvoidmechanical strength of separator

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent applies composite materials by combining organic fiber web with inorganic oxide coating layer to create a separator structure that achieves both thinness and mechanical strength. The composite structure allows the separator to maintain adequate strength even at reduced thickness, enabling higher electrode loading amounts while preserving structural integrity.

Inventive Principle:

Principle #40Composite materials

2Temperature

If an inorganic oxide coating layer is provided on the separator surface to improve heat resistance, then the thermal stability is improved, but the pores are clogged causing deterioration of lithium-ion pathway function

Engineering Contradiction:

Improveheat resistance of separatorVSAvoidlithium-ion pathway function

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies local quality by creating a porous inorganic oxide coating layer that maintains pore structure rather than completely covering the surface. The coating is applied locally on the separator surface with controlled porosity (30-70%) to provide heat resistance while preserving lithium-ion transport pathways. This selective local modification allows thermal stability improvement without blocking ion transport.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses porous materials by forming a porous inorganic oxide coating layer on the separator. The coating layer contains controlled porosity (30-70%) that allows lithium-ion transport while providing thermal stability. The porous structure prevents complete pore clogging and maintains the separator's function as a lithium-ion pathway even at elevated temperatures.

Inventive Principle:

Principle #31Porous materials

3Temperature

If a coating layer is added to improve heat resistance and mechanical strength, then the thermal stability is improved, but the thickness increases reducing battery energy density

Engineering Contradiction:

Improveheat resistance of separatorVSAvoidthickness of separator

Core Design Contradiction:

TemperatureVSLength of stationary object

Solution Approach 1:

The patent uses porous materials to create a thin coating layer with controlled porosity (30-70%) that provides heat resistance without significant thickness increase. The porous structure allows the coating to be effective at minimal thickness, preserving battery energy density while improving thermal stability.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent applies parameter changes by controlling the thickness of the inorganic oxide coating layer within a specific range (1-10 μm) and adjusting porosity (30-70%) to optimize the balance between heat resistance and thickness. By modifying these parameters, the separator achieves improved thermal stability with minimal impact on overall thickness and energy density.

Inventive Principle:

Principle #35Parameter changes

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 a secondary battery with improved lifespan and high-rate characteristics due to enhanced heat resistance, mechanical strength, and electrolyte-impregnation properties, preventing structural distortion and maintaining lithium-ion migration efficiency.

Implementation Method 1

vapor-depositing heat-resistant inorganic particles

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Implementation Method 2

forming a composite coating layer including a hydrophilic organic compound

Methodology Applied

Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Data Source

PatentUS12183947B2Separator, including composite coating layer containing inorganic particles and hydrophilic organic compound arranged on web of organic fibers, preparation method of same, and secondary battery comprising same

Publication Date: 2024.12.31 SAMSUNG SDI CO LTD

AI summary

The present disclosure relates to a separator, a method of preparing the separator, and a secondary battery comprising the separator, the separator including: a web structure of organic fibers; and a composite coating layer arranged on the organic fibers, wherein the composite coating layer includes heat-resistant inorganic particles and a hydrophilic organic compound.