Gas-Phase Film Forming for Porous Electrode Foil Stress Control
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Solution Overview
Problem
Conventional film-forming devices using a gas phase method on metal foils with porous portions often result in defects such as cracks or voids, particularly during the latter half of the film formation process.
Innovation Solution
A film-forming device with a conveyor system that controls the stress applied to the metal foil to 21 N/mm2 or less, using a control unit to manage tension and prevent swinging, ensuring stable film formation without defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gas phase method is used to form a film on metal foil with porous portions, then film formation efficiency is improved, but defects such as cracks or voids occur on the metal foil
Solution Approach 1:
The patent changes the physical state parameter of the anodizing solution from liquid to gas phase, enabling film formation on porous metal foil while controlling stress parameters to prevent defects. The gas phase anodizing allows oxygen to penetrate and react with the porous structure without causing the mechanical stress that leads to cracks and voids.
Solution Approach 2:
The patent replaces the conventional liquid phase anodizing mechanism with a gas phase mechanism. Instead of using liquid electrolyte that causes swelling and stress, the invention uses gaseous oxygen or oxygen-containing gas to perform the anodizing reaction, thereby eliminating the mechanical stress that causes film defects.
2Ease of repair
If conventional liquid phase anodization is used, then defects can be repaired, but film formation on porous metal foil causes swelling and stress leading to cracks
Solution Approach 1:
The patent replaces the liquid phase chemical mechanism with a gas phase mechanism. The gas phase anodizing avoids the swelling effect caused by liquid electrolyte absorption in the porous structure, thereby preventing the generation of internal stress that leads to cracks and maintains metal foil integrity.
Solution Approach 2:
The patent uses a gas phase environment (oxygen or oxygen-containing gas) that is less intrusive compared to liquid electrolyte. The gas phase provides a more uniform and controllable environment for anodizing that reduces mechanical stress on the porous metal foil 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
The device effectively prevents defects in the film formation process, resulting in high-performance electrode foils with stable quality and reduced crack or void generation.
Implementation Method 1
a metal foil having a porous portion on a main surface
Implementation Method 2
a conveyor provided downstream of the film-forming region and drawing the metal foil from the film-forming region, and a control unit that controls a stress applied to the metal foil from the conveyor to 21 N/mm2 or less
Data Source
AI summary
A film-forming device disclosed is a film-forming device for forming a film on a metal foil having a porous portion on a main surface thereof by a gas phase method, and includes a film-forming region in which the film is formed on the metal foil, conveyors to provided downstream of the film-forming region and drawing the metal foil from the film-forming region, and a control unit that controls the stress applied to the metal foil from the conveyors to 21 N/mm2 or less. This provides a film-forming device which does not cause defects easily on a film-forming target metal foil.