Electrode Paste Particle Size Control for Fast Drying
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Solution Overview
Problem
Current methods for producing electrodes for electricity storage devices are inefficient in terms of time and energy consumption during the drying process, often requiring special facilities and resulting in suboptimal electrode performance.
Innovation Solution
A method involving the production of a paste with a solids fraction material content ratio of 60 to 80 mass % and an abundance ratio of aggregates with a particle size of 20 μm or smaller, achieving high-rate drying without special equipment, by controlling the paste's state to optimize drying conditions such as temperature and wind velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional paste coating methods are used with standard drying conditions, then electrode production can proceed with standard equipment, but drying time and energy consumption are excessive
Solution Approach 1:
The invention changes the physical parameters of the paste by controlling the particle size distribution of the electrode active material. Specifically, it uses a cumulative volume-particle size distribution where the gradient at 20% cumulative volume is 0.003 to 0.015 μm⁻¹ and at 80% cumulative volume is 0.003 to 0.010 μm⁻¹. This parameter optimization enables high-rate drying with reduced time and energy consumption.
Solution Approach 2:
The invention performs preliminary action by optimizing the particle size distribution of the electrode active material before the drying process. By controlling the particle size distribution parameters in advance, the paste achieves optimal packing and solvent evaporation characteristics, allowing subsequent drying to proceed rapidly with standard equipment.
2Reliability
If particle size distribution is optimized for compression flow during pressing, then electrode capacity is improved, but production method efficiency is not enhanced
Solution Approach 1:
The invention changes the particle size distribution parameters to achieve dual benefits. The cumulative volume-particle size distribution gradients are controlled to optimize both compression flow during pressing (improving electrode capacity) and drying rate (improving production efficiency). This simultaneous optimization of multiple parameters resolves the contradiction between electrode performance and production efficiency.
3Loss of time
If high solids fraction material content is used in paste, then drying time is reduced, but paste viscosity increases making coating difficult
Solution Approach 1:
The invention optimizes the particle size distribution parameters to enable high solids fraction material content (60-80 mass %) while maintaining acceptable paste viscosity. The controlled cumulative volume-particle size distribution gradients ensure proper particle packing and flow characteristics, allowing the paste to remain coatable despite high solids content, thus reducing drying time without sacrificing coating processability.
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 approach significantly reduces the time and energy required for drying, preventing defects like creases and cracks in the electrode material layer, while maintaining high performance and efficiency in producing electrodes for various electricity storage devices.
Implementation Method 1
aggregates of solids fraction material that contains at least an electrode active material and a binder, and the aggregates are dispersed in a solvent
Implementation Method 2
drying the current collector coated with the paste to form the electrode active material layer formed of the solids fraction material
Data Source
AI summary
A method of producing an electrode for an electricity storage device includes producing a paste to form an electrode active material layer, in which aggregates of a solids fraction material that contains at least an electrode active material and a binder are dispersed in a solvent, coating the paste on a surface of a current collector, and drying the current collector coated with the paste, to form the electrode active material layer formed of the solids fraction material. The paste is produced in such a manner that a content ratio of the solids fraction material in the paste is 60 to 80 mass %, an abundance ratio for the aggregates with a particle size that is equal to or smaller than 20 μm is at least 99%, and a viscosity at 25° C. and a shear rate of 40 s−1 is 200 to 5,000 mPa·s.