Solvent-Free Electrode Fabrication via Aqueous Binder Dispersion
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Solution Overview
Problem
Current electrode production methods face challenges such as high energy consumption and environmental impact in the wet process due to solvent evaporation, and agglomeration issues in the dry process, particularly with soft binder particles, which affect uniform distribution and performance.
Innovation Solution
A hybrid process involving the blending of dry active powdery electrode materials with an aqueous binder dispersion, specifically using a fluoropolymer like PVDF, to form a uniform blend that is then applied to an electroconductive substrate, ensuring small particle size and uniform distribution without agglomeration, while reducing energy consumption and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet process with solvent solution or dispersion is used, then good dispersion and small particle size are achieved, but large amount of solvent must be evaporated causing high energy consumption and environmental impact
Solution Approach 1:
The patent extracts and removes the solvent component from the wet process, using only aqueous binder dispersion without organic solvents like NMP. This eliminates the need for solvent evaporation while maintaining the dispersion quality benefits of the wet process.
Solution Approach 2:
The patent changes the binder form from dry powder to aqueous dispersion, allowing the binder to be applied in a dispersed state that ensures uniform distribution, then removed via drying without requiring energy-intensive solvent evaporation.
2Loss of energy
If dry process is used, then energy consumption is reduced and environmental impact is minimized, but binder particles tend to agglomerate affecting uniform distribution
Solution Approach 1:
The patent performs preliminary dispersion of the binder in aqueous medium before application to the electrode materials. This pre-dispersion step ensures uniform distribution of binder particles before the drying process, preventing agglomeration that would occur in direct dry mixing.
Solution Approach 2:
The patent uses aqueous dispersion as an intermediary medium to carry the binder particles uniformly throughout the electrode material mixture. The water-based dispersion acts as a temporary carrier that ensures even distribution before being removed through drying.
3Loss of energy
If dry polymer powder is dry-blended with dry active powdery electrode-forming materials, then energy savings are achieved, but agglomeration of soft binder particles occurs during drying or storage
Solution Approach 1:
The patent creates a stable aqueous dispersion copy of the binder system that maintains uniform particle distribution during storage and processing. This dispersion state serves as a stable intermediate form that prevents the agglomeration issues inherent in dry powder handling.
Solution Approach 2:
The patent creates a composite system combining aqueous dispersion with dry electrode materials, forming a hybrid blend that maintains the stability and uniformity benefits of dispersion while enabling the energy efficiency of dry processing.
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
This hybrid process achieves better dispersion and interconnectivity of active electrode materials, reducing binder usage, lowering manufacturing costs, and enhancing the performance and efficiency of energy storage devices by maintaining the advantages of both wet and dry processes.
Implementation Method 1
blending of dry active powdery electrode forming materials with an aqueous binder dispersion to form a uniform blend
Implementation Method 2
the water added with the dispersion is easily removed with heat applied during the electrode-forming process
Data Source
AI summary
The invention relates to an electrode formed by the blending of dry active powdery electrode forming materials with an aqueous binder dispersion, and the subsequent adhering of the wet binder/dry active powdery electrode-forming materials blend to an electroconductive substrate, resulting in an electrode. The aqueous binder is preferably a fluoropolymer, and more preferably polyvinylidene fluoride (PVDF). The hybrid process provides the good dispersion and small particle size of a wet process, with the energy savings and reduced environmental impact of a dry process. The resulting electrode is useful in energy-storage devices.