Microporous Membrane Composition for Electrolyte Wettability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

High density polyethylene polymers used in lithium ion battery membranes face challenges in wettability with electrolyte solutions, affecting ion mobility and battery efficiency due to their inherent low flowability and surface properties.

Innovation Solution

A polymer composition incorporating high density polyethylene particles and a surface tension reducing additive, such as a hydrophilic inorganic filler or organic polymer, is formulated to enhance wettability, which can include a grafted copolymer of polyethylene and maleic acid anhydride, and may be further treated with techniques like plasma treatment to improve ion permeability and battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high density polyethylene is used for membrane production, then mechanical strength and chemical resistance are improved, but wettability with electrolyte solution deteriorates

Engineering Contradiction:

Improvemechanical strengthVSAvoidwettability with electrolyte solution

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by combining high density polyethylene with surface tension reducing additives (such as surfactants, wetting agents, or hydrophilic polymers) to create a composite membrane structure. This composite approach maintains the mechanical strength of polyethylene while introducing components that improve wettability with electrolyte solutions, thereby resolving the contradiction between strength and wettability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the surface tension parameter of the polyethylene membrane by incorporating surface tension reducing additives. This parameter change allows the membrane to maintain its structural integrity while improving its interaction with electrolyte solutions, thus resolving the contradiction between mechanical strength and wettability.

Inventive Principle:

Principle #35Parameter changes

2Strength

If molecular weight of polyethylene is increased, then mechanical properties are improved, but flowability in molten state deteriorates

Engineering Contradiction:

Improvemechanical propertiesVSAvoidflowability in molten state

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the processing parameters by using gel-processing instead of conventional melt extrusion. This alternative processing method enables the use of high molecular weight polyethylene with improved mechanical properties while overcoming the flowability issues that would prevent conventional processing.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical melt extrusion process with a gel-processing method. This substitution allows high molecular weight polyethylene to be processed into membranes without requiring the material to flow in molten state, thereby maintaining mechanical properties while enabling manufacturability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If microporous structure is created for ion permeability, then ion transport is improved, but mechanical strength deteriorates

Engineering Contradiction:

Improveion permeabilityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses porous materials by creating a microporous structure in the polyethylene membrane through gel-processing. This porous structure enables ion transport while the specific fabrication method and material composition maintain adequate mechanical strength, resolving the contradiction between ion permeability and mechanical strength.

Inventive Principle:

Principle #31Porous 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 improved wettability of the polymer composition increases ion mobility within lithium ion batteries, enhancing battery efficiency and lifetime by facilitating better interaction between the membrane and electrolyte solution.

Implementation Method 1

a surface tension reducing additive that increases the wettability of the polymer composition and of articles made from the composition

Methodology Applied

Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

the microporous membrane permits ions to pass through due to the porous nature of the material

Methodology Applied

Scientific EffectIon permeability through porous structure: Porosity

Implementation Method 3

The article may be treated with a plasma or with a corona discharge

Methodology Applied

Scientific EffectPlasma treatment: Plasma

Data Source

PatentUS20230383105A1Microporous Membrane With Enhanced Electrolyte Wettability

Publication Date: 2023.11.30 CELANESE INTERNATIONAL CORP

AI summary

A polymer composition for producing gel extruded articles is described. The polymer composition contains polyethylene particles combined with a plasticizer and one or more surface tension reducing techniques. In one aspect, the surface tension reducing technique includes adding a filler or chemical component to the polyethylene polymer for increasing wettability. Alternatively, the surface tension reducing technique can be a surface treatment, such as a plasma treatment. Polymer articles made in accordance with the present disclosure can have dramatically increased wettability properties. In one embodiment, the polymer composition is used to form a porous membrane for use as a separator in electronic devices.