Fuel Cell Separator Carbon Coating via UV Activation
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Solution Overview
Problem
The challenge in manufacturing a separator for a fuel cell is ensuring adhesion between a titanium oxide layer and a carbon thin film, which is difficult due to the strong and dense nature of the titanium oxide layer, leading to increased manufacturing costs from the need for additional steps like forming an intermediate layer or removing the titanium oxide layer.
Innovation Solution
Irradiating the titanium oxide layer with light of a wavelength equal to or shorter than 390 nm to activate it photocatalytically, improving surface free energy and adhesion with the carbon coating film, thereby eliminating the need for an intermediate layer or titanium oxide removal, and using nitrogen or argon-nitrogen gas mixtures for bombardment in CVD processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate layer is formed between the titanium oxide layer and the carbon thin film layer to ensure adhesion, then the adhesion between the layers is improved, but the number of manufacturing steps is increased and manufacturing costs are increased
Solution Approach 1:
The patent applies preliminary action by irradiating the titanium oxide layer with ultraviolet light before forming the carbon thin film layer. This pre-treatment activates the titanium oxide layer surface, creating reactive sites that improve adhesion without requiring an intermediate layer. The ultraviolet irradiation modifies the surface properties of the titanium oxide layer in advance, enabling direct bonding with the subsequent carbon film.
Solution Approach 2:
The patent replaces the mechanical/physical approach of adding an intermediate layer with a chemical/photochemical approach using ultraviolet irradiation. Instead of mechanically adding another material layer to improve adhesion, the method uses light energy to chemically activate the titanium oxide surface, creating bonding sites that enable direct adhesion to the carbon film.
2Reliability
If the titanium oxide layer is removed from the surface of the titanium substrate to form a carbon thin film layer, then the adhesion is improved, but the number of steps is increased and manufacturing costs are increased
Solution Approach 1:
The patent extracts or removes the titanium oxide layer through ultraviolet irradiation treatment, converting it from a barrier to adhesion into an activated surface that promotes adhesion. Rather than completely removing the oxide layer through complex etching processes, the method selectively modifies the oxide layer properties to enable direct carbon film formation.
Solution Approach 2:
The patent changes the surface parameters of the titanium oxide layer through ultraviolet irradiation. The irradiation alters the surface energy, reactivity, and chemical state of the titanium oxide layer, transforming it from a low-adhesion state to a high-adhesion state that directly bonds with carbon films without requiring removal or additional layers.
3Ease of manufacture
If the titanium oxide layer is kept intact to simplify manufacturing, then the manufacturing cost is reduced, but the adhesion between the titanium oxide layer and the carbon thin film layer is poor
Solution Approach 1:
The patent changes the surface parameters of the intact titanium oxide layer through ultraviolet irradiation. By modifying the surface energy and chemical reactivity of the oxide layer in place, the method maintains the layer's integrity while dramatically improving its adhesion properties, allowing direct bonding with the carbon film.
Solution Approach 2:
The patent replaces mechanical removal or addition of layers with a photochemical treatment that modifies the existing titanium oxide layer's surface properties. This substitution maintains manufacturing simplicity while achieving reliable adhesion through chemical activation rather than physical modification.
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 manufacturing costs by simplifying the process and enhancing adhesion between the titanium oxide and carbon layers, allowing for direct contact without additional steps, thus improving the efficiency and cost-effectiveness of the carbon coating film formation.
Implementation Method 1
irradiating the surface of the titanium oxide layer of the titanium substrate with light having a wavelength of equal to or shorter than 390 nm
Implementation Method 2
irradiating the surface of the titanium oxide layer with light having a wavelength of equal to or shorter than 390 nm to activate it photocatalytically
Implementation Method 3
forming the carbon coating film on the surface of the titanium oxide layer that is irradiated with the light at the time of irradiating the surface of the titanium oxide layer of the titanium substrate with light having a wavelength of equal to or shorter than 390 nm
Data Source
AI summary
A manufacturing method of a separator for a fuel cell is a method for forming a carbon coating film on a titanium substrate, which has a titanium oxide layer on a surface of the titanium substrate, by CVD. The method includes a step of making a state in which the titanium substrate, which has the titanium oxide layer on the surface of the titanium substrate, is placed into a vacuum atmosphere, an irradiation step of irradiating a surface of the titanium oxide layer of the titanium substrate with light having a wavelength of equal to or shorter than 390 nm before the carbon coating film is formed or while the carbon coating film is being formed, and a step of forming the carbon coating film on the surface of the titanium oxide layer that is irradiated with light in the irradiation step.