Electrode Wet Granules Two-Stage Stirring Refinement
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Solution Overview
Problem
The existing manufacturing methods for non-aqueous electrolyte secondary battery electrodes, such as those described in JP 2002-110145 A, face issues with malleability degradation and pinhole generation due to high-speed stirring, and coarse particle size leading to streaks in the electrode material layer during rolling.
Innovation Solution
A method involving the formation of wet granules by stirring a mixture of electrode active material, binding material, and solvent at two distinct stirring speeds, with the second speed being faster and shorter to refine the particle size to 400 μm or smaller, enhancing malleability and preventing consolidation, thereby improving the film-forming properties of the electrode material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If stirring is performed at a high speed for a long period of time during the kneading process, then the wet granules are consolidated, but the malleability of the wet granules during rolling is degraded and pinholes may be generated in the formed electrode material layer
Solution Approach 1:
The patent applies periodic action by using two-stage stirring with different speeds and durations. First, low-speed stirring is performed for a longer period to achieve consolidation, then high-speed stirring is performed for a shorter period to refine particle size without excessive consolidation. This periodic variation in stirring intensity resolves the contradiction between consolidation and maintaining malleability.
Solution Approach 2:
The patent changes the parameters of stirring speed and time in two distinct stages. The first stage uses low speed with longer time for consolidation, while the second stage uses high speed with shorter time for particle refinement. This parameter optimization prevents over-consolidation while achieving adequate consolidation, thereby maintaining both stability and film-forming properties.
2Duration of action of moving object
If stirring is performed at a low speed in the kneading process, then the particle size of the wet granules becomes coarsened, but coarse granules are caught on the rolls during rolling and streaks may be generated in the electrode material layer
Solution Approach 1:
The patent uses periodic action with two-stage stirring: first low-speed stirring for consolidation, then high-speed stirring for particle size refinement. This ensures that particle size is reduced to appropriate dimensions without requiring excessive low-speed stirring time, thereby preventing streak formation during rolling.
Solution Approach 2:
The patent optimizes stirring parameters by applying high speed for a short duration in the second stage. This achieves sufficient particle size refinement (reducing coarse granules that cause streaks) without the need for prolonged low-speed stirring, thus maintaining film-forming properties while achieving adequate particle size reduction.
3Measurement precision
If the stirring time at the second stirring speed is extended, then the particle size is further refined, but the wet granules are consolidated and pinholes are generated in the electrode material layer
Solution Approach 1:
The patent precisely controls the second stirring speed and time parameters to achieve optimal particle size refinement (400 μm or smaller) without excessive consolidation. By limiting the high-speed stirring time to less than 5 seconds, the patent achieves sufficient particle refinement while preventing over-consolidation that would cause pinholes.
Solution Approach 2:
The patent applies partial action by using high-speed stirring for a limited, optimized duration. This provides just enough particle size refinement (achieving 400 μm or smaller) without applying excessive high-speed stirring that would cause over-consolidation and pinhole formation. The stirring time is precisely controlled to be less than 5 seconds.
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 reduces streaks and pinholes in the electrode material layer, enhancing the film-forming properties and maintaining the malleability of the wet granules during rolling, resulting in a more effective electrode material layer formation.
Implementation Method 1
a process of granulating the electrode active material by stirring the mixture at a first stirring speed, and a process of stirring the granulated electrode active material at a second stirring speed that is faster than the first stirring speed so as to be refined to an average particle size of 400 μm or smaller
Data Source
AI summary
A manufacturing method of an electrode according to the invention includes: a process of forming wet granules by stirring a mixture of an electrode active material, a binding material, and a solvent; and a process of forming an electrode material layer on a current collector by rolling the wet granules. The process of forming the wet granules includes: a process of granulating the electrode active material by stirring the mixture at a first stirring speed; and a process of stirring the granulated electrode active material at a second stirring speed that is faster than the first stirring speed so as to be refined to an average particle size of 400 μm or smaller. A stirring time at the second stirring speed is shorter than a stirring time at the first stirring speed and is shorter than 5 seconds.