Polyolefin Battery Separators with Surfactant Coatings

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Solution Overview

Problem

Existing lithium ion battery separators, particularly those made from polyolefins, face challenges with wettability and electrolyte retention, leading to inefficient ion movement and potential short circuits due to their hydrophobic nature, which affects battery performance and cycle life.

Innovation Solution

A multilayer microporous separator membrane with nonwoven layers and surfactant coatings or treatments is developed, enhancing wettability and stability by laminating nonwoven layers to polyolefin membranes and applying surfactants like lithium dodecylbenzene sulfonate, improving electrolyte wetting and retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polyolefin separators are used, then manufacturing simplicity and cost-effectiveness are improved, but wettability and electrolyte retention deteriorate due to hydrophobic nature

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidwettability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining polyolefin base material with hydrophilic additives (such as silane-modified polyethylene, polypropylene-glycidyl methacrylate, or inorganic hydrophilic particles) to create a separator that maintains the manufacturing advantages of polyolefin while gaining improved wettability and electrolyte retention properties through the hydrophilic components

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If polyolefin separators are used, then manufacturing simplicity is improved, but ion movement efficiency deteriorates due to poor electrolyte retention

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidion movement efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent uses composite materials incorporating hydrophilic additives within the polyolefin matrix to enhance electrolyte retention, which directly improves ion movement efficiency while preserving the manufacturing simplicity of polyolefin-based separators

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the porous structure of the separator to enhance electrolyte uptake and retention. The controlled porosity and pore size distribution allow for improved ion transport pathways while maintaining the structural integrity and manufacturing advantages of polyolefin separators

Inventive Principle:

Principle #31Porous materials

3Reliability

If nonwoven layers are laminated to polyolefin membranes, then wettability and stability are improved, but device complexity increases

Engineering Contradiction:

ImprovewettabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a composite structure by laminating nonwoven layers (such as polypropylene nonwoven fabric) to the polyolefin membrane. This composite approach enhances wettability and mechanical stability while maintaining a relatively simple layered structure that can be manufactured using conventional lamination techniques

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent merges multiple functional layers (polyolefin membrane providing barrier and structural functions, nonwoven layer providing wettability and porosity) into a single integrated separator component, improving overall performance while keeping the combined structure manageable and manufacturable

Inventive Principle:

Principle #5Merging (Combining)

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 significantly enhances the wettability and stability of the separator membranes, leading to improved charging capacity and extended cycle life of lithium ion batteries, particularly in consumer electronics and electric vehicles.

Implementation Method 1

applying surfactants like lithium dodecylbenzene sulfonate, improving electrolyte wetting and retention

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 2

enhancing wettability and stability by laminating nonwoven layers to polyolefin membranes and applying surfactants

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS11658333B2Microporous battery separators including polyolefin layer and non-woven layer with alkylbenzene sulfonic acid lithium salt surfactant, lithium batteries utilizing the same, and methods of manufacture of the same

Publication Date: 2023.05.23 CELGARD LLC

AI summary

In accordance with at least certain embodiments, the present invention is directed to novel, improved, coated, or treated separator membranes, separators or membrane based separators for lithium batteries. The membranes or separators may include non-woven layers, improved surfactant treatments, or combinations thereof. The separators or membranes are useful for solvent electrolyte lithium batteries, especially rechargeable lithium ion batteries, and provide improved performance, wettability, cycling ability, and/or recharging efficiency.