Battery Separator Functional Layer for Post-Electrolyte Adhesion

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Solution Overview

Problem

Conventional non-aqueous secondary battery functional layers face challenges in achieving excellent adhesiveness after immersion in electrolyte solution, which affects the overall battery characteristics such as ion conductivity and cycle performance.

Innovation Solution

A slurry composition containing particulate polymer A with a reactive functional group-containing monomer unit and a glass-transition temperature between 30°C and 95°C, and particulate polymer B with a glass-transition temperature below 30°C, is used to form a functional layer with enhanced adhesiveness and ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional functional layer is formed using a single type of binder or simple mixture of binders, then the manufacturing process is simple, but the adhesiveness after immersion in electrolyte solution is insufficient

Engineering Contradiction:
Improveadhesiveness after immersionVSAvoidbinder composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining two distinct polymer types (polymer A with Tg of 30-95°C and polymer B with Tg below 30°C) in the functional layer. This composite structure enables the layer to maintain both structural integrity and adhesive properties after immersion in electrolyte solution, resolving the contradiction between simplicity and performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by carefully controlling the glass-transition temperatures of the polymers used. Polymer A has Tg between 30-95°C and polymer B has Tg below 30°C, creating a specific thermal parameter range that optimizes adhesiveness after electrolyte immersion while managing the complexity of material selection.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the glass-transition temperature of the binder is too high, then the structural stability is improved, but the adhesiveness after immersion in electrolyte solution deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidadhesiveness after immersion
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent segments the binder function into two distinct polymer components with different Tg ranges. Polymer A (Tg 30-95°C) provides structural stability, while polymer B (Tg below 30°C) ensures adhesiveness after immersion. This segmentation resolves the contradiction by distributing different functional requirements to different material segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different thermal properties to different polymer components within the functional layer. The higher-Tg polymer provides local structural stability, while the lower-Tg polymer provides local adhesive quality, achieving overall performance optimization.

Inventive Principle:
Principle #3Local quality

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 proposed solution results in a functional layer with improved adhesiveness and ion conductivity, leading to better battery characteristics, including enhanced cycle performance and blocking resistance after immersion in electrolyte solution.

Implementation Method 1

a functional layer formed by applying a slurry composition for a secondary battery functional layer containing components such as a binder onto a substrate such as a separator substrate

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the functional layer having excellent ion conductivity of lithium ions

Methodology Applied
Scientific EffectIon conductivity: Conduction (electrical)

Data Source

PatentUS20240421430A1Slurry composition for non-aqueous secondary battery functional layer, separator for non-aqueous secondary battery, and non-aqueous secondary battery
Publication Date: 2024.12.19 ZEON CORP

AI summary

A slurry composition for a non-aqueous secondary battery functional layer contains a particulate polymer A including a reactive functional group-containing monomer unit and a particulate polymer B. The particulate polymer A has a glass-transition temperature of not lower than 30° C. and not higher than 95° C., the particulate polymer B has a glass-transition temperature of lower than 30° C., and the particulate polymer A has a volume-average particle diameter of not less than 250 nm and not more than 800 nm.