Battery Electrode Drying with Shielded Edge Heat Control
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Solution Overview
Problem
The uneven drying speed between the side and central areas of a secondary battery electrode leads to cracking, potentially causing fires due to charge capacity deterioration or separator damage, as the solvent evaporates faster on the side areas where more heat is concentrated.
Innovation Solution
A manufacturing method and apparatus that use a shielding device to control the heat distribution by measuring the height difference between the central and side areas of the coating layer, moving the shielding device to positions where the offset value is less than a reference value, and directing hot air to prevent over-drying of the side areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot air is supplied to dry the coating layer, then the drying speed is improved, but the heat distribution becomes uneven causing side areas to dry faster than central areas
Solution Approach 1:
The patent applies local quality by making different parts of the nozzle have different functions: the central area supplies hot air for drying while the side areas are shielded to reduce heat supply. This resolves the contradiction by creating non-uniform heat distribution that compensates for the non-uniform drying characteristics of different electrode regions, achieving overall uniform drying.
Solution Approach 2:
The nozzle is segmented into a central area and side areas with different functions. The shielding device selectively shields the side areas while leaving the central area exposed, creating differentiated heat supply zones that address the uneven drying speed problem while maintaining high overall drying efficiency.
2Productivity
If the side area dries faster due to concentrated heat flow, then the drying efficiency is improved, but cracks are generated on the electrode
Solution Approach 1:
The shielding device is positioned in advance to block hot air from reaching the side areas before excessive drying occurs. This preliminary protective action prevents the concentration of heat that would cause rapid drying and subsequent cracking, thereby maintaining electrode integrity while still allowing efficient drying through the central area.
Solution Approach 2:
The patent converts the harmful concentrated heat flow that causes cracking into a beneficial controlled heat distribution pattern. By strategically shielding side areas, the system uses the natural heat concentration effect to dry the central area efficiently while preventing overheating of side areas, thus transforming a potential defect source into a drying advantage.
3Manufacturing precision
If a shielding device is added to control heat distribution, then the drying uniformity is improved, but the device complexity increases
Solution Approach 1:
The shielding device acts as an intermediary element between the hot air source and the electrode side areas. This simple mediating structure selectively blocks heat flow to achieve uniform drying without requiring complex modifications to the nozzle or heating system, thus improving drying uniformity with minimal added complexity.
Solution Approach 2:
The shielding device can be dynamically adjusted or positioned to optimize heat distribution during the drying process. This dynamic capability allows the system to adapt to varying drying conditions and maintain uniform drying across different stages, achieving high manufacturing precision without permanently complicating the device structure.
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 method reduces the difference in drying speed between the side and central areas, preventing cracks and increasing the yield of electrodes by ensuring uniform drying, thereby enhancing the reliability and safety of secondary batteries.
Implementation Method 1
measuring the height of a coating layer through a height sensor... outputting light to a coating layer by an output portion of a height sensor; receiving light by a receiving portion of a height sensor
Implementation Method 2
drying the coating layer... by hot air supplied through each of nozzles other than the selected nozzle among a plurality of nozzles and by hot air supplied through a central area of the selected nozzle
Implementation Method 3
the solvent of the slurry to be evaporated per unit time... the flow of hot air is concentrated in the side area of the electrode and the amount of heat transferred to the side area is greater
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Provided is a manufacturing method of an electrode for secondary battery, the method comprising: forming a coating layer on a current collector; obtaining an offset value representing a height difference in the width direction of the coating layer; moving a shielding device to a position where the offset value is less than a reference value; and drying the coating layer.