Non-aqueous Battery Binder Composition for Peel Strength

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Solution Overview

Problem

Conventional binder compositions for non-aqueous secondary battery electrodes lack sufficient peel strength and cycle characteristics, limiting the performance of non-aqueous secondary batteries.

Innovation Solution

A binder composition combining a first particulate polymer with an aliphatic conjugated diene monomer unit, having a volume average particle diameter of 0.6 µm to 2.5 µm, and a second particulate polymer with an aliphatic conjugated diene and aromatic vinyl monomer units, having a volume average particle diameter of 0.01 µm to 0.5 µm, is used to enhance binding capacity and cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a binder composition containing two types of particulate polymers of differing particle diameters is used, then peel strength is improved, but cycle characteristics remain insufficient

Engineering Contradiction:
Improvepeel strengthVSAvoidcycle characteristics
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the volume average particle diameter of the first particulate polymer within 0.6 µm to 2.5 µm and the second within 0.01 µm to 0.5 µm, along with specifying the aliphatic conjugated diene monomer unit content (≥90 mass% for first, 20-60 mass% for second). These parameter optimizations simultaneously improve peel strength and cycle characteristics, resolving the contradiction between strength and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite binder system combining two specific particulate polymers with defined compositional and size parameters. The first particulate polymer (≥90 mass% aliphatic conjugated diene, 0.6-2.5 µm) and second particulate polymer (20-60 mass% aliphatic conjugated diene, 0.01-0.5 µm) work synergistically to provide both strong adhesion (peel strength) and long-term stability (cycle characteristics), achieving dual improvement through material composition design.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional binder compositions are used, then manufacturing is simple, but both peel strength and cycle characteristics are insufficient

Engineering Contradiction:
Improvebinder composition simplicityVSAvoidpeel strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent maintains ease of manufacture by using a straightforward two-component particulate polymer system with clear specification ranges. The manufacturing process remains simple mixing and coating, but the controlled parameters (particle diameter 0.6-2.5 µm and 0.01-0.5 µm, monomer composition ratios) enable superior peel strength without complicating the production workflow.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional binder compositions are used, then manufacturing is simple, but cycle characteristics remain insufficient

Engineering Contradiction:
Improvebinder composition simplicityVSAvoidcycle characteristics
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent achieves improved cycle characteristics while maintaining simple manufacturing by optimizing the volume average particle diameter (first: 0.6-2.5 µm, second: 0.01-0.5 µm) and aliphatic conjugated diene monomer unit content (first: ≥90 mass%, second: 20-60 mass%). These parameter specifications enable better electrode stability during cycling without requiring complex manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3358661B1Non-aqueous secondary battery electrode binder composition, non-aqueous secondary battery electrode slurry composition, non-aqueous secondary battery electrode, and non-aqueous secondary battery
Publication Date: 2021.06.30 ZEON CORP

AI summary

Provided is a binder composition for a non-aqueous secondary battery electrode capable of forming an electrode for a non-aqueous secondary battery that has excellent peel strength and can cause a non-aqueous secondary battery to display excellent cycle characteristics. The binder composition for a non-aqueous secondary battery electrode contains: a first particulate polymer including an aliphatic conjugated diene monomer unit in a proportion of more than 90 mass% and having a volume average particle diameter of at least 0.6 µm and not more than 2.5 µm; and a second particulate polymer including an aliphatic conjugated diene monomer unit in a proportion of at least 20 mass% and not more than 60 mass% and having a volume average particle diameter of at least 0.01 µm and not more than 0.5 µm.