Slurry Composition for Non-Aqueous Battery Layers

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Solution Overview

Problem

Existing non-aqueous secondary battery functional layers lack improved heat contraction resistance and high-temperature cycle characteristics, with existing slurry and coating liquids exhibiting poor dispersibility.

Innovation Solution

A slurry composition comprising a water-soluble polymer with an average degree of polymerization between 50 and 450, preferably a cellulosic derivative like carboxymethylcellulose, along with a binder and a wetting agent, enhances dispersibility and heat contraction resistance of non-aqueous secondary battery functional layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing slurry compositions are used to form functional layers, then the functional layers can be formed on substrates, but the dispersibility of the slurry is poor and heat contraction resistance is insufficient

Engineering Contradiction:
Improveheat contraction resistanceVSAvoiddispersibility of slurry
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the molecular weight parameter of the water-soluble polymer to a specific range (10,000-100,000 g/mol) and controls the content ratio between water-soluble polymer and binder (1:9 to 9:1). These parameter optimizations simultaneously improve dispersibility and heat contraction resistance, resolving the technical contradiction between ease of manufacture and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite slurry system combining water-soluble polymer, binder, non-conductive particles, and optional wetting agents. This composite material approach enhances both the dispersibility of the slurry and the heat contraction resistance of the formed functional layer, addressing both aspects of the technical contradiction.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If water-soluble polymer with high degree of polymerization is used, then film uniformity improves, but dispersibility of slurry decreases

Engineering Contradiction:
Improvefilm uniformityVSAvoiddispersibility of slurry
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent optimizes the degree of polymerization parameter to a specific range (10,000-100,000 g/mol), avoiding both too low and too high values. This parameter optimization achieves the right balance where the polymer provides sufficient film-forming capability for uniformity while maintaining adequate dispersibility for easy manufacturing.

Inventive Principle:
Principle #35Parameter changes

3Strength

If functional layer is formed to improve heat resistance and strength, then battery member performance improves, but heat contraction resistance and high-temperature cycle characteristics remain insufficient

Engineering Contradiction:
Improveheat resistance and strength of functional layerVSAvoidheat contraction resistance and high-temperature cycle characteristics
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the content ratio of water-soluble polymer to binder within 1:9 to 9:1, and controls the water-soluble polymer content at 1-50 wt% of total slurry. These parameter changes ensure the functional layer achieves both sufficient strength/heat resistance and excellent heat contraction resistance with improved high-temperature cycle characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The water-soluble polymer acts as an intermediary component that enhances the heat contraction resistance of the functional layer without compromising its strength and heat resistance. This intermediary substance enables the functional layer to maintain structural integrity while resisting heat-induced contraction.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 slurry composition improves the dispersibility and heat contraction resistance of non-aqueous secondary battery functional layers, leading to enhanced high-temperature cycle characteristics of non-aqueous secondary batteries.

Implementation Method 1

a water-soluble polymer with an average degree of polymerization between 50 and 450, preferably a cellulosic derivative like carboxymethylcellulose

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

enhances dispersibility and heat contraction resistance of non-aqueous secondary battery functional layers

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

a functional layer composed of a porous membrane layer formed by binding non-conductive particles using a binder

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

applying a slurry composition for functional layers which contains non-conductive particles, a binder, and a dispersion medium, such as water, onto a surface of a substrate, and then drying the applied slurry composition

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11394029B2Slurry composition for non-aqueous secondary battery functional layers, non-aqueous secondary battery functional layer, and non-aqueous secondary battery
Publication Date: 2022.07.19 ZEON CORP

AI summary

A slurry composition for non-aqueous secondary battery functional layers contains non-conductive particles, a water-soluble polymer having an average degree of polymerization of 50 or more and 450 or less, a binder, and water.