Acrylic Binder for Lithium Battery Adhesion and Rate
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Solution Overview
Problem
Conventional lithium secondary battery binders, such as PVDF, require large amounts and organic solvents, leading to environmental issues and compromising battery rate and lifespan characteristics when replaced with water-based binders.
Innovation Solution
A binder composed of polymer particles from copolymerization of (meth)acrylic acid ester, unsaturated carboxylic acid, and vinyl monomers, optimizing wettability and adhesion to improve battery quality, using water as a dispersion medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PVDF is used as binder, then adhesion is excellent, but environmental problem occurs due to organic solvent and battery rate characteristics deteriorate due to large binder amount
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by using copolymerizable monomers (acrylic acid, methacrylic acid, and their esters) instead of PVDF, and changes the dispersion medium from organic solvent to water. This parameter change achieves both excellent adhesion and environmental friendliness while improving rate characteristics
Solution Approach 2:
The invention uses a composite binder system comprising multiple monomer components (acrylic acid, methacrylic acid, and their esters) polymerized together. This composite material approach creates a binder with synergistic properties that simultaneously provide adhesion, environmental compatibility, and excellent rate characteristics
2Object-affected harmful factors
If water-based binder composition is used, then environmental friendliness is improved, but battery rate characteristics and lifespan characteristics are degraded
Solution Approach 1:
The invention optimizes the molecular weight, composition ratio, and structural parameters of the water-based polymer binder to achieve both environmental friendliness and excellent battery performance. The specific parameter range (polymerization conditions, monomer ratios) is carefully controlled to balance adhesion, wettability, and electrochemical stability
Solution Approach 2:
The invention creates local quality differences in the binder structure through copolymerization, where different monomer units provide different functions: acrylic acid units provide adhesion, ester units provide flexibility and wettability. This local differentiation enables the binder to simultaneously achieve environmental compatibility and excellent rate/lifespan characteristics
3Strength
If binder amount is increased, then adhesion is sufficient, but electrode active material content is reduced
Solution Approach 1:
The invention changes the adhesion parameter by using a polymer with optimized molecular weight and functional group composition that provides superior binding strength per unit mass. This allows achieving sufficient adhesion with reduced binder quantity, thereby increasing active material content
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 binder enhances battery capacity, rate characteristics, and lifespan by ensuring excellent adhesion and wettability, while being environmentally friendly and reducing the amount needed, thus overcoming the limitations of traditional binders.
Implementation Method 1
which allows electrode active material particles capable of lithium intercalation/deintercalation to be fixed and linked among themselves, and between the particles and a collector
Implementation Method 2
there is a unique interrelation between the wettability of the binder and the battery quality
Data Source
AI summary
Disclosed is a binder, which comprises polymer particles obtained by polymerization of: (a) 1˜80 parts by weight of a (meth)acrylic acid ester monomer; (b) 1˜20 parts by weight of an unsaturated carboxylic acid monomer; and (c) 0.001˜40 parts by weight of a vinyl monomer, based on 100 parts by weight of the binder polymer, and which allows electrode active material particles capable of lithium intercalation/deintercalation to be fixed and linked among themselves, and between the particles and a collector. An electrode comprising the binder, and a lithium secondary battery having the electrode are also disclosed. Further, a method for evaluating interrelation between wettability of a binder to an electrolyte and quality of a battery comprising the binder is disclosed.