Coanda Effect Hot Air Blower for Wrinkle-Free Electrode Drying
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Solution Overview
Problem
The generation of wrinkles in uncoated regions of secondary battery electrodes during high-temperature drying due to differences in shrinkage rates between the electrode current collector and the electrode material leads to defects and reduced productivity.
Innovation Solution
A Coanda effect hot air blower and drying apparatus that discharges hot air in a direction parallel to the width of the electrode web, using inclined guide fins to guide hot air flow and suppress wrinkles by increasing surface contact with support rollers, thereby reducing the generation of wrinkles and improving product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-temperature air flow is used to quickly dry the electrode material, then drying speed is improved, but wrinkles are generated in the uncoated regions due to differential shrinkage
Solution Approach 1:
The patent applies different drying conditions to different regions of the electrode web. The Coanda effect nozzles are positioned to direct hot air flow specifically at the uncoated regions where wrinkles form, while the coated regions receive different airflow patterns. This localized approach allows aggressive drying where needed without causing differential shrinkage wrinkles, resolving the contradiction between drying speed and surface flatness.
Solution Approach 2:
The patent replaces conventional mechanical drying methods with a fluid dynamics-based approach using the Coanda effect. Instead of using mechanical means to control web tension and prevent wrinkles, the invention uses adherent hot air flow that naturally follows the web surface contour, providing uniform heating and drying while maintaining web stability, thus achieving both high drying speed and surface flatness.
2Manufacturing precision
If hot air flow is directed at the uncoated regions to prevent wrinkles, then surface flatness is improved, but the kinetic energy of the hot air is not fully utilized
Solution Approach 1:
The Coanda effect nozzles generate a continuous sheet of adherent hot air flow that continuously follows the electrode web surface. This continuous flow ensures that the kinetic energy of the hot air is consistently utilized along the entire length of the web, maintaining both surface flatness through uniform heating and maximizing energy efficiency through sustained adhesive flow without interruption or waste.
Solution Approach 2:
The patent employs pneumatic principles through the Coanda effect, where a jet of hot air adheres to and follows the contour of the electrode web surface. This pneumatic approach uses the coherence and adhesion properties of the air flow to uniformly distribute thermal energy across the web, fully utilizing the kinetic energy of the hot air while maintaining surface flatness through controlled, adherent flow patterns.
3Productivity
If the electrode web is fed at high speed through the drying apparatus, then productivity is improved, but wrinkles are more likely to form due to increased stress
Solution Approach 1:
The patent replaces mechanical tension control methods with a thermal-fluid approach. Instead of relying on mechanical means to control web tension during high-speed feeding, the Coanda effect nozzles use adherent hot air flow to uniformly heat and dry the web, reducing differential shrinkage stresses that cause wrinkles. This allows high-speed feeding while maintaining surface flatness through thermal management rather than mechanical control.
Solution Approach 2:
The patent changes the drying parameters by using the Coanda effect to create a distributed, adherent hot air flow pattern that maintains consistent temperature and humidity conditions across the web surface during high-speed feeding. This parameter control through fluid dynamics prevents differential shrinkage and wrinkle formation even at high feeding speeds, resolving the contradiction between productivity and manufacturing precision.
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 effectively suppresses wrinkles in uncoated regions, reducing defects and enhancing the productivity of secondary battery electrodes by ensuring uniform drying and stable web feeding.
Implementation Method 1
a Coanda effect hot air blower configured to discharge hot air in order to dry a web of an electrode
Data Source
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AI summary
Disclosed are a Coanda effect hot air blower configured to discharge hot air in order to dry a web of an electrode of a secondary battery in which coated regions and uncoated regions are alternately disposed in a width direction and a secondary battery electrode drying apparatus including the same. The Coanda effect hot air blower includes a housing in which a nozzle slit is formed so as to extend in a width direction of the web to discharge hot air and a hot air generating unit. The housing is provided therein with a guide side wall to guide hot air to the nozzle slit, and the guide side wall is provided with a plurality of first inclined guide fins and a plurality of second inclined guide fins extending so as to be inclined in opposite directions with respect to a center point of the web in the width direction.