Multi-Slot Die Coater Manifold Geometry for Uniform Slurry Flow
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Solution Overview
Problem
Conventional dual slot die coaters face issues with uniform flow and stagnation of electrode active material slurry, leading to agglomeration and non-uniform coating, which affects the quality and productivity of secondary battery electrodes.
Innovation Solution
A multi-slot die coater design with inwardly recessed manifolds having surfaces with different angles to prevent stagnation, ensuring uniform flow and minimizing residence time of the slurry, featuring a lower and upper slot with manifolds in the die blocks and spacers to adjust slot widths, allowing for simultaneous coating of two types of slurries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional manifold with constant angle is used, then the structure is simple, but the slurry flow becomes non-uniform and stagnation occurs
Solution Approach 1:
The manifold is designed with different angle regions: a first region with a first angle and a second region with a second angle different from the first. This local variation in geometric quality ensures uniform slurry flow distribution to different slots while preventing stagnation in any particular region, thereby achieving both manufacturing feasibility and coating uniformity.
Solution Approach 2:
The manifold employs asymmetric angle configuration where the angles in different regions are intentionally made different from each other. This asymmetric design creates optimized flow paths that prevent stagnant zones and ensure uniform slurry distribution across all slots, resolving the contradiction between structural simplicity and coating precision.
2Speed
If the manifold angle is increased to improve flow, then flow speed increases, but slurry may not be properly distributed to all slots
Solution Approach 1:
Different regions of the manifold have different angles optimized for their specific functions: some regions have larger angles to maintain flow speed and prevent stagnation, while other regions have smaller angles to ensure proper distribution and filling of slots. This local optimization achieves both high flow speed and uniform distribution simultaneously.
3Device complexity
If a single-slot die coater is used, then the device is simple, but productivity is low due to sequential coating requirements
Solution Approach 1:
The die coater is segmented into multiple slots that can simultaneously coat different electrode active material layers. Each slot operates independently to apply coating to the current collector, enabling parallel processing of multiple layers and significantly increasing productivity while maintaining a relatively simple overall device structure.
Solution Approach 2:
Multiple coating slots are merged into a single die coater device, allowing simultaneous coating operations. This consolidation of multiple coating functions into one device achieves high productivity without requiring multiple separate coaters, thus balancing device complexity with manufacturing throughput.
4Productivity
If thick electrode active material layer is applied in one coat, then productivity is improved, but binder and conductive material migrate during drying causing non-uniform electrode
Solution Approach 1:
The coating process is segmented into multiple slots that can apply different electrode active material layers simultaneously or in sequence. This segmentation allows optimization of each layer's thickness and composition, preventing the migration issues that occur with excessively thick single-layer coatings while maintaining high productivity through parallel 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
The multi-slot die coater achieves uniform coating and high productivity by preventing agglomeration and surface defects, ensuring consistent electrode layer formation at desired thicknesses, even under high-speed or wide-scale conditions.
Implementation Method 1
the first manifold is a chamber of an inwardly recessed shape, and includes a first surface and a second surface at a location close to the lower slot, the first surface and the second surface having different angles to the lower slot
Data Source
AI summary
There is provided a multi-slot die coater including a manifold for a uniform flow of an electrode active material slurry without stagnation. The multi-slot die coater of the present disclosure includes a first manifold in which a first coating solution is received and a second manifold in which a second coating solution is received. The first manifold is a chamber of an inwardly recessed shape, and includes a first surface and a second surface having different angles to a lower slot at a location close to the lower slot, and the angle of the first surface closest to the lower slot is formed at a level of 30˜70% of the second surface following the first surface.