Rotating-Slit Coating Die for Uniform Electrode Slurry Discharge
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Solution Overview
Problem
Conventional coating dies for secondary battery electrode plates face issues with uneven electrode slurry discharge, leading to uneven active material layer thickness and impaired battery performance, which requires frequent adjustment of choke bars due to temperature changes and viscosity variations.
Innovation Solution
A coating die with a rotating body that forms a variable slit within the manifold, allowing for adjustable paint discharge by varying the length of the slit based on the position, which helps equalize the discharge amount across the coating width, and a supply device with an intermittent valve for precise coating control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional coating die with choke bars is used, then the discharge amount can be adjusted in the coating width direction, but frequent manual adjustments are required due to temperature changes and viscosity variations
Solution Approach 1:
The patent applies the dynamics principle by replacing static choke bars with a rotating body that can dynamically adjust slit lengths. The rotating body is divided into multiple segments that can independently rotate to change the effective slit length at different positions along the coating width, enabling real-time adaptation to temperature and viscosity changes without frequent manual interventions.
Solution Approach 2:
The patent implements parameter changes by varying the slit length parameter through rotation of the rotating body segments. Each segment can be positioned to create different slit lengths (first slit, second slit, third slit) at different coating width positions, allowing the discharge amount to be adjusted by changing the geometric parameter of the flow path rather than by manual choke bar manipulation.
2Manufacturing precision
If the discharge amount is adjusted using conventional choke bars, then uneven discharge can be corrected, but the coating process complexity increases due to manual intervention requirements
Solution Approach 1:
The rotating body with independently rotatable segments provides a dynamic adjustment mechanism that reduces operational complexity. Instead of manually adjusting multiple choke bars, the system uses a unified rotating structure that can be controlled to achieve the desired slit length distribution, simplifying the adjustment process while maintaining film thickness uniformity.
Solution Approach 2:
The rotating body serves multiple functions: it acts as both a flow path definition structure and an adjustment mechanism. The same rotating segments that create the slits also serve as the adjustment elements, eliminating the need for separate choke bars and reducing overall device complexity while achieving film thickness uniformity.
3Manufacturing precision
If a rotating body with variable slit lengths is used, then discharge amount can be equalized across coating width, but the device structure becomes more complex
Solution Approach 1:
The rotating body is nested within the manifold structure, with the rotating segments fitting into the manifold's internal geometry. This nesting allows the variable slit length mechanism to be integrated into the existing manifold design rather than adding a completely separate structure, reducing overall device complexity while achieving discharge uniformity.
Solution Approach 2:
The patent merges the flow path definition function and the adjustment mechanism function into a single integrated structure. The rotating body segments both define the slit geometry and provide the adjustment capability, combining multiple functions into one element to reduce the number of separate components and simplify the overall device structure.
Data Source
AI summary
A coating die includes a manifold, a discharge port, and a rotating body rotatably accommodated in the manifold, an outer surface of the rotating body and an inner surface of the manifold being capable of forming a first slit. The manifold, the discharge port, and the rotating body are elongated in a first direction intersecting a discharge direction of the paint. The rotating body is rotatable about a rotational axis, has a long circumferential portion having a predetermined first length in the outer surface, and has a short circumferential portion having a second length shorter than the first length at a position in the outer surface displaced from the long circumferential portion, the long circumferential portion forming the first slit longer than the first slit formed by the short circumferential portion.