Coated Anode Active Particles for Stronger Li-Ion Electrode Adhesion
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Solution Overview
Problem
Lithium ion batteries produced using coated active material particles often have insufficient mechanical strength, leading to damage and deteriorated cycle characteristics during the battery production process and usage.
Innovation Solution
Coated negative electrode active material particles with a specific polymer compound containing (meth)acrylic acid as a constituent monomer and a compound such as tetrahydrothiophene 1,1-dioxide, ethylene carbonate, or vinylene carbonate, which improves adhesion and elasticity, allowing for the production of lithium ion batteries with enhanced mechanical strength and cycle characteristics without a solvent removal process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional coated active material particles are used, then the production process can be simplified without solvent removal, but the mechanical strength of the electrode becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the coating layer by specifying that it must contain a polymer compound with (meth)acrylic acid as a constituent monomer at 70-95 wt%. This parameter change transforms the coating from a simple binder layer into a chemically optimized adhesive system that provides both ease of manufacture and sufficient mechanical strength.
Solution Approach 2:
The patent creates a composite coating layer system combining specific polymer compounds (with (meth)acrylic acid) and compounds (A) that work synergistically. This composite material approach allows the coating to simultaneously provide adhesion, elasticity, and mechanical strength without requiring complex solvent removal processes.
2Quantity of substance
If the coating layer contains insufficient polymer compound, then the production cost is reduced, but the adhesion between particles deteriorates leading to poor cycle characteristics
Solution Approach 1:
The patent optimizes the concentration parameter of the polymer compound in the coating layer to 70-95 wt% of (meth)acrylic acid content. This precise parameter control ensures that the coating contains just enough polymer to provide excellent adhesion and cycle characteristics while avoiding excessive material usage that would increase costs.
Solution Approach 2:
The patent introduces compounds (A) as intermediary substances that work together with the polymer compound containing (meth)acrylic acid. These compounds act as mediators that enhance the adhesive properties of the polymer, allowing effective adhesion at optimized polymer concentrations that balance cost and performance.
3Stability of the object's composition
If the coating layer lacks elasticity, then the structural stability is improved, but the adhesion between coated particles deteriorates
Solution Approach 1:
The patent creates a composite coating system where the polymer compound providing structural stability is combined with compounds (A) that contribute elasticity. This composite approach allows the coating layer to simultaneously maintain structural integrity and provide the elasticity needed for strong particle adhesion during battery cycling.
Solution Approach 2:
The patent applies different functional properties to different aspects of the coating layer: the polymer compound with (meth)acrylic acid provides local adhesive quality at the particle interface, while the overall coating matrix provides structural stability. This local differentiation of material properties resolves the contradiction between stability and adhesion.
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 solution enables the production of lithium ion batteries with improved mechanical strength and cycle characteristics by enhancing the adhesion between coated negative electrode active material particles, maintaining the structure during charging and discharging, and reducing production costs and environmental impact by eliminating the need for solvent removal.
Implementation Method 1
the compound (A) functions as a plasticizer for the polymer compound, imparts excellent elasticity to the coating layer
Implementation Method 2
a distillation process in which the organic solvent is distilled off after the mixing process
Data Source
AI summary
Coated negative electrode active material particles for lithium ion batteries in which at least a part of the surface of negative electrode active material particles is covered with a coating layer containing a polymer compound and a compound (A), the polymer compound is a polymer including (meth)acrylic acid as a constituent monomer, the weight proportion of (meth)acrylic acid in the polymer based on the weight of the polymer is 70 to 95 wt %, and the compound (A) is at least one selected from the group consisting of tetrahydrothiophene 1,1-dioxide, ethylene carbonate and vinylene carbonate.