Fluidized Bed Coating for Energy Storage Electrodes
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Solution Overview
Problem
Current energy storage device electrode fabrication techniques face challenges such as high costs and resource inefficiencies due to solvent removal processes in wet methods and potential damage to active materials in dry high-shear processes, limiting electrode performance and material choices.
Innovation Solution
A fluidized bed coating apparatus is used to vaporize a polymer dispersion and coat active electrode components, such as graphite or lithium metal oxide, with a polymer binder like polytetrafluoroethylene, forming a self-supporting electrode film without high-shear processing, which reduces manufacturing costs and preserves material integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet electrode fabrication is used, then homogeneous distribution of active and binder materials is achieved, but large amounts of power and time are required for solvent removal
Solution Approach 1:
The invention changes the physical state of the binder from liquid (in wet fabrication) to powder form, enabling direct dry mixing and elimination of the drying step. This parameter change transforms the fabrication process from wet to dry state, resolving the contradiction between homogeneous distribution and energy consumption for solvent removal.
Solution Approach 2:
The invention extracts and removes the liquid solvent component from the fabrication process entirely. By using powder-based binders instead of liquid binders, the harmful factor of requiring energy-intensive solvent removal is eliminated while maintaining material distribution homogeneity through controlled powder mixing.
2Loss of energy
If conventional dry electrode fabrication is used, then solvent removal problems are avoided, but active materials may be damaged due to high-shear processing
Solution Approach 1:
The invention replaces high-shear mechanical mixing with low-shear mixing mechanisms. By using gentle mixing methods such as ribbon mixing or tumbling mixing instead of high-shear dispersers, the active materials are not subjected to damaging mechanical forces while still achieving uniform distribution of binder and active material.
Solution Approach 2:
The invention employs dynamic mixing approaches where the mixing intensity and duration can be controlled and adjusted. By using variable speed mixing and extended mixing times at lower intensities, homogeneous mixing is achieved without the peak shear forces that damage active materials in conventional high-shear processes.
3Ease of manufacture
If thin electrode films are fabricated, then manufacturing costs are reduced, but energy density of the energy storage device is limited
Solution Approach 1:
The invention changes the binder from liquid to powder form, which enables the fabrication of thicker electrode films without the need for energy-intensive drying processes. This parameter change allows simultaneous achievement of thicker films (higher energy density) and cost-effectiveness by eliminating the drying step that normally limits film thickness.
Solution Approach 2:
The invention enables local optimization of electrode film thickness throughout the electrode structure. By using dry fabrication with powder binders, different regions of the electrode can be made with optimized thicknesses to maximize energy density while maintaining manufacturing efficiency, without being constrained by uniform drying requirements.
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 method enables the production of thicker electrode films with improved energy density and reduced manufacturing costs, while minimizing surface damage to active materials, thus enhancing the electrical performance of energy storage devices.
Implementation Method 1
vaporizing the liquid portion of the polymer dispersion within the fluidized bed coating apparatus to form a dried polymer
Implementation Method 2
forming a fluidized bed comprising the second component of the electrode mixture within the fluidized bed coating apparatus
Data Source
AI summary
An apparatus for forming an electrode film mixture can have a first source including a polymer dispersion comprising a liquid and a polymer, a second source including a second component of the electrode film mixture, and a fluidized bed coating apparatus including a first inlet configured to receive from the first source the dispersion, and a second inlet configured to receive from the second source the second component.