Pore-Filled Battery Separator to Block Metal Column Growth

Solution Overview

Problem

Lithium secondary batteries are prone to micro-short circuits due to the growth of metal columns from the negative electrode through the pores of the separator, which reduces their lifetime and performance.

Innovation Solution

A separator for lithium secondary batteries is designed with a coating layer containing inorganic particles and a fluorine-based ionomer that selectively fills either the first or second pores, preventing the growth of metal columns while maintaining ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a porous separator is used to maintain ion conductivity, then lithium ions can move freely, but metal columns can grow through the pores causing micro-short circuits

Engineering Contradiction:

Improveprevention of micro-short circuitsVSAvoidmetal column growth through pores

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The separator is designed with different properties in different regions: the bulk separator maintains high porosity for ion conductivity, while the coating layer on the surface has filled pores to prevent metal column growth. This local differentiation allows simultaneous achievement of ion transport and short circuit prevention.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator combines a porous base material (polyolefin or ceramic) with a coating layer containing inorganic particles and binder that fills the pores. This composite structure integrates the ion-conducting function of porous materials with the protective function of the filled coating layer.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the pores of the separator are filled to prevent metal column growth, then micro-short circuits are prevented, but ion conductivity is reduced

Engineering Contradiction:

Improveprevention of micro-short circuitsVSAvoidion conductivity

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The separator is designed with different properties in different regions: the bulk separator maintains high porosity for ion conductivity, while the coating layer on the surface has filled pores to prevent metal column growth. This local differentiation allows simultaneous achievement of ion transport and short circuit prevention.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator combines a porous base material (polyolefin or ceramic) with a coating layer containing inorganic particles and binder that fills the pores. This composite structure integrates the ion-conducting function of porous materials with the protective function of the filled coating layer.

Inventive Principle:

Principle #40Composite materials

3Temperature

If a coating layer with inorganic particles is applied to the separator, then thermal stability is improved, but the structure becomes more complex

Engineering Contradiction:

Improvethermal stabilityVSAvoidseparator structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The separator combines a porous base material (polyolefin or ceramic) with a coating layer containing inorganic particles and binder that fills the pores. This composite structure integrates the ion-conducting function of porous materials with the protective function of the filled coating layer.

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 effectively prevents micro-short circuits, enhances thermal and mechanical stability, and maintains high ionic conductivity, thereby improving the battery's lifetime and discharge capacity.

Implementation Method 1

an ion conductive polymer which selectively fills either one of all of the first pores and all of the second pores

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

a coating layer which is located on the surface of the substrate, includes inorganic particles and a binder

Methodology Applied

Scientific EffectCoating: Coatings

Data Source

PatentEP3817095B1Separator for lithium secondary battery, manufacturing method of the same, lithium secondary battery including the same

Publication Date: 2025.07.02 LG ENERGY SOLUTION LTD

Figure 1
Figure 2

AI summary

The present disclosure relates to a separator for lithium secondary battery, a method for manufacturing same, and a lithium secondary battery including the same. Specifically, in one embodiment of the present disclosure, by filling the pores of the separator, the present invention physically inhibits the metal column capable of growing on the surface of the negative electrode from moving toward the positive electrode, inhibits a micro-short circuit of the lithium secondary battery, and ultimately improves the lifetime of the lithium secondary battery. In addition, by controlling the type of filling the pores of the separator and the type of the polymer filling it, the output characteristics of the lithium secondary battery are secured and improved.