Non-aqueous Battery Functional Layer Binder Composition

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Solution Overview

Problem

Non-aqueous secondary battery functional layers with water-soluble polymers as binders face issues with inadequate redispersibility of non-conductive particles and flexibility, leading to potential curling during drying or stress.

Innovation Solution

A composition combining a water-soluble polymer with a (meth)acrylamide monomer unit in high proportion and a particulate polymer, optimizing the weight average molecular weight and content to enhance redispersibility and flexibility, preventing curling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a water-soluble polymer is used as a binder in the composition for a non-aqueous secondary battery functional layer, then binding capacity and homogeneity are improved, but redispersibility of non-conductive particles deteriorates and flexibility of the functional layer deteriorates

Engineering Contradiction:
ImprovehomogeneityVSAvoidredispersibility
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent uses a composite binder system combining a water-soluble polymer (providing homogeneity and binding capacity) with a water-insoluble polymer (providing redispersibility and flexibility). This composite approach allows the functional layer to maintain both good initial homogeneity and excellent redispersibility after storage, resolving the contradiction between stability and ease of operation.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If a water-soluble polymer is used as a binder in the composition for a non-aqueous secondary battery functional layer, then binding capacity and homogeneity are improved, but flexibility of the functional layer deteriorates

Engineering Contradiction:
ImprovehomogeneityVSAvoidflexibility
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The patent employs a composite binder system where a water-soluble polymer provides homogeneity and binding capacity, while a water-insoluble polymer provides flexibility and prevents curling. This combination allows the functional layer to maintain both good homogeneity and excellent flexibility, resolving the contradiction between stability and shape characteristics.

Inventive Principle:
Principle #40Composite materials

3Duration of action of stationary object

If the composition for a non-aqueous secondary battery functional layer is stored for a long period, then production logistics are improved, but non-conductive particles sediment and redispersibility deteriorates

Engineering Contradiction:
Improvestorage periodVSAvoidredispersibility
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The patent uses a composite binder system where the water-insoluble polymer component provides excellent redispersibility after long-term storage. This allows the composition to be stored for extended periods without significant sedimentation issues, and when needed, the non-conductive particles can be easily redispersed, resolving the contradiction between storage duration and ease of operation.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3336930B1Composition for non-aqueous secondary cell functional layer, functional layer for non-aqueous secondary cell, and non-aqueous secondary cell
Publication Date: 2020.12.02 ZEON CORP

AI summary

Provided is a composition for a non-aqueous secondary battery functional layer that has excellent redispersibility of non-conductive particles and enables formation of a functional layer for a non-aqueous secondary battery having excellent flexibility. Also provided are a functional layer for a non-aqueous secondary battery formed using this composition for a non-aqueous secondary battery functional layer and a non-aqueous secondary battery including this functional layer for a non-aqueous secondary battery. The composition for a non-aqueous secondary battery functional layer contains non-conductive particles, a water-soluble polymer that includes a (meth)acrylamide monomer unit in a proportion of 40 mass% or more and has a weight average molecular weight of less than 3.0 × 105, and a particulate polymer.