Reciprocating Coating Die for Uniform Electrode Slurry Thickness
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Solution Overview
Problem
Conventional methods for coating electrode active material slurry on an electrode current collector result in non-uniform thickness, leading to inefficiencies and discarded regions, which affect the economic efficiency and yield of secondary battery manufacturing.
Innovation Solution
An apparatus with a reciprocally movable coating die that adjusts its position and speed relative to the electrode current collector to ensure uniform coating thickness across the balcony, main, and drag regions, without altering the active material slurry composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed coating die is used to coat active material slurry on a continuously moving electrode current collector, then the coating process is simple and continuous, but the coating thickness becomes non-uniform due to inertial force and viscous force acting on the slurry in different regions
Solution Approach 1:
The coating die is made movable along the traveling direction of the electrode current collector, transitioning from a fixed position to a dynamic position-adjustable system. This allows the coating die to change its position relative to different regions (balcony, main, drag) of the coating area, enabling uniform coating thickness across all regions by compensating for inertial and viscous forces through controlled movement.
2Adaptability or versatility
If the active material slurry has high viscosity, then the slurry can be coated selectively on specific areas, but the slurry distribution becomes non-uniform due to viscous force acting in opposite directions on different regions
Solution Approach 1:
The coating die moves dynamically to compensate for the effects of high viscosity. By adjusting its position along the traveling direction of the electrode current collector, the coating die counteracts the viscous force that causes non-uniform distribution, ensuring that even with high viscosity slurry, uniform coating thickness is achieved across all regions including balcony, main, and drag areas.
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 solution achieves uniform coating thickness, minimizing dead space and enhancing economic efficiency and yield by adjusting the relative speed of the coating die to the electrode current collector, thus preventing non-uniformity and optimizing the use of all regions.
Implementation Method 1
when the active material slurry S ejected from the coating die 20 encounters the coating areas T of the electrode current collector E, inertial force I acts on the active material slurry S in an opposite direction to a moving direction of the electrode current collector E
Implementation Method 2
the active material slurry S has a high coefficient of viscosity due to physical properties thereof. Thus, as shown in FIG. 2, in each of the coating areas T, viscous force V selectively acts on the active material slurry S
Data Source
AI summary
An apparatus for coating electrode active material slurry includes: a transfer unit continuously transferring an electrode current collector in a predetermined process direction; and a coating die which is reciprocally movable in the process direction or an opposite direction to the process direction and coats the active material slurry on a predetermined coating area of the electrode current collector transferred by the transfer unit, wherein the coating die stands by at a predetermined coating start position and, when a balcony region corresponding to a leading end of the coating area reaches the coating start position, coats the active material slurry on the balcony region while moving from the coating start position to a main coating position that is spaced apart from the coating start position by a predetermined distance in the opposite direction.