Nanoporous Multilayer Battery Separator for High-Temperature Stability

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Solution Overview

Problem

Existing lithium batteries face challenges in achieving increased dimensional stability at elevated temperatures while requiring lower coating weights and thicknesses, and reducing manufacturing costs.

Innovation Solution

A multilayer separator comprising a porous polymeric layer with nanoporous inorganic oxide/polymer composite layers on both sides, utilizing boehmite or boehmite and nitride particles with small crystallite sizes and high polymer volume fractions, providing enhanced thermal stability and ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If inorganic oxide/polymer coating layers are applied to polymeric separators to improve dimensional stability at elevated temperatures, then thermal stability is improved, but coating weight and coating thickness increase

Engineering Contradiction:

Improvedimensional stability at elevated temperaturesVSAvoidcoating weight

Core Design Contradiction:

Stability of the object's compositionVSWeight of stationary object

Solution Approach 1:

The patent employs nanoporous inorganic oxide particles (5-90 nm crystallite size) as the coating material. The porous structure allows the coating to provide thermal stability while maintaining lower coating weight and thickness, as the porous structure reduces material density while preserving the heat-resistant framework that prevents polymer collapse at elevated temperatures.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent creates a composite inorganic oxide/polymer coating layer where nanoporous inorganic oxide particles are dispersed in a polymer binder. This composite structure combines the thermal stability of inorganic oxide with the flexibility and adhesion of polymer, achieving dimensional stability at lower coating weights compared to pure inorganic coatings.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

Engineering Contradiction:

Improvedimensional stability at elevated temperaturesVSAvoidcoating thickness

Core Design Contradiction:

Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The nanoporous structure of the inorganic oxide particles creates a coating with high void content, allowing the coating to achieve the required thermal stability function with reduced thickness. The porous framework provides structural support at elevated temperatures while occupying less physical space than dense coatings would require.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent changes the physical state and structure of the coating material by using nanoscale crystallite sizes (5-90 nm) instead of microscale particles. This parameter change in particle size enables the coating to provide equivalent thermal stability with significantly reduced thickness, as nanoparticles can form more efficient heat-resistant networks at thinner film depths.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If lower coating weights and thicknesses are used to reduce manufacturing costs, then manufacturing cost is reduced, but dimensional stability at high temperature deteriorates

Engineering Contradiction:

Improvemanufacturing costVSAvoiddimensional stability at high temperature

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The nanoporous inorganic oxide particles provide high surface area to volume ratio, creating a more efficient heat-resistant network per unit weight. This allows the coating to achieve required dimensional stability at lower weights, reducing material costs while maintaining performance.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

By changing the crystallite size parameter to the nanoscale range (5-90 nm), the coating material exhibits enhanced thermal stability per unit mass compared to microscale particles. This parameter change allows thinner, lighter coatings to achieve the same dimensional stability, reducing both material cost and manufacturing complexity.

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 achieves lower coating weights and thicknesses, improved dimensional stability at high temperatures, and increased safety by preventing lithium metal dendrite growth and transition metal ion diffusion, while maintaining excellent ionic conductivity.

Implementation Method 1

provides increased dimensional stability at high temperature

Methodology Applied

Scientific EffectThermal stability:

Implementation Method 2

a high level of porosity for excellent ionic conductivity of the electrolyte in the pores of the separator

Methodology Applied

Scientific EffectIonic conductivity:

Implementation Method 3

increased safety by preventing lithium metal dendrite growth

Methodology Applied

Scientific EffectPhysical barrier effect:

Implementation Method 4

preventing transition metal ion diffusion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS12412923B2Multilayer nanoporous separator

Publication Date: 2025.09.09 LG ENERGY SOLUTION LTD

AI summary

A separator for a lithium battery having (a) a porous polymeric layer, such as a polyethylene layer; and (b) a nanoporous inorganic particle/polymer layer on both sides of the polymeric layer, the nanoporous layer having an inorganic oxide and one or more polymers; the volume fraction of the polymers in the nanoporous layer is about 15% to about 50%, and the crystallite size of the inorganic oxide is 5 nm to 90 nm.