Battery Separator Polyethylene Resin for Uniform Extrusion Melting

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Ultra-high molecular weight polyethylene resins used in battery separators face challenges in processing due to low flowability, making it difficult to achieve uniform melting and mechanical strength in the extrusion process.

Innovation Solution

A polyethylene resin with a single particle morphology and a double peak melting point (125 °C to 132 °C and 133 °C to 136 °C) is developed, combining low and high molecular weight polymers to enhance extrusion processability and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ultra-high molecular weight polyethylene resin is used to improve mechanical strength of separator, then separator strength is improved, but extrusion processability deteriorates due to low flowability and difficulty in uniform melting

Engineering Contradiction:

Improveseparator mechanical strengthVSAvoidextrusion processability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by controlling the molecular weight distribution of polyethylene resin. Specifically, it uses a resin with viscosity average molecular weight of 500,000 to 1.2 million g/mol and molecular weight distribution (Mw/Mn) of 3.0 to 7.0, which optimizes both flowability for extrusion and mechanical strength for separator performance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining polyethylene resin with specific additives including 0.01 to 5 parts by weight of antioxidant and 0.01 to 3 parts by weight of nucleating agent per 100 parts by weight of polyethylene resin. This composite approach enhances both processability and final product properties.

Inventive Principle:

Principle #40Composite materials

2Strength

If higher molecular weight polyethylene resin is used to increase separator strength, then mechanical properties are improved, but uniform melting in extruder becomes difficult achieving

Engineering Contradiction:

Improveseparator mechanical strengthVSAvoiduniformity of melting

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by precisely controlling molecular weight distribution parameters. It specifies viscosity average molecular weight of 500,000 to 1.2 million g/mol and molecular weight distribution (Mw/Mn) of 3.0 to 7.0, which ensures uniform melting behavior while maintaining high mechanical strength in the separator.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by pre-optimizing the resin characteristics before extrusion. The molecular weight distribution and thermal properties are controlled in advance during resin manufacturing, ensuring that the material melts uniformly in the extruder without requiring complex process adjustments.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If polyethylene resin with optimized melting properties is used to improve extrusion processability, then extrusion processability is improved, but molecular weight may be reduced affecting mechanical strength

Engineering Contradiction:

Improveextrusion processabilityVSAvoidseparator mechanical strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent simultaneously optimizes multiple parameters to resolve this contradiction. It specifies viscosity average molecular weight of 500,000 to 1.2 million g/mol for adequate strength, molecular weight distribution (Mw/Mn) of 3.0 to 7.0 for uniform melting, and melting point of 128°C to 138°C for good extrusion processability. The combination of these parameters achieves both processability and mechanical strength.

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 polyethylene resin exhibits improved extrusion processability and mechanical strength, reducing the formation of gels and ensuring uniform melting, thereby enhancing the quality of the porous separator film.

Implementation Method 1

the melting point forms a double peak in which a first peak is in the range of 125 °C to 132 °C and a second peak is in the range of 133 °C to 136 °C

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentEP4001325B1Polyethylene resin for secondary battery separator, method for manufacturing the same, and separator to which the same is applied

Publication Date: 2025.01.22 HANWHA TOTALENERGIES PETROCHEMICAL CO LTD

AI summary

The present invention relates to a polyethylene resin for a separator capable of securing excellent mechanical strength of a porous separator film as a molded product while exhibiting excellent extrusion processability, a method for manufacturing the same, and a separator for a secondary battery to which the polyethylene resin is applied. The polyethylene resin is a single particle and has a melting point exhibiting a double peak in which a first peak is in the range of 125 °C to 132 °C and a second peak is in the range of 133 °C to 136 °C