Fuel Cell Separator Resin Coating Adhesion
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Solution Overview
Problem
Fuel cell separators face durability issues due to corrosion from product water containing acids and fluorine ions, leading to seal failures and potential separator corrosion, despite existing anticorrosion resin coating layers which may not provide sufficient adhesion with resin frames or gaskets.
Innovation Solution
A fuel cell separator with a metal plate and an anticorrosion resin coating layer having a surface roughness of 0.5 to 13.5 μm, achieved through electrodeposition with fillers or roughening treatments like shot blasting, to enhance adhesion between the resin coating layer and its counterpart members, such as resin frames or gaskets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anticorrosion resin coating layer is formed on the separator surface through electrodeposition, then corrosion resistance is improved, but adhesion between the resin coating layer and resin frame or gasket deteriorates due to extremely high surface planarity
Solution Approach 1:
A primer coating layer is applied beforehand to the separator surface before the main resin coating layer. This primer layer serves as an intermediate that enhances adhesion between the metal separator and the subsequent resin coating, preventing delamination while maintaining corrosion resistance.
Solution Approach 2:
The coating system uses a composite structure with a primer layer (containing phosphoric acid or silane coupling agents) combined with a main resin coating layer. This composite approach provides both corrosion protection and improved adhesion properties that neither layer could achieve alone.
2Object-affected harmful factors
If a smooth resin coating layer is formed on the separator, then corrosion protection is achieved, but seal durability deteriorates due to insufficient mechanical interlocking with seal members
Solution Approach 1:
The coating system provides different functional properties at different interfaces: the primer layer optimizes adhesion to the metal separator, while the main resin layer provides corrosion protection. This localized functional differentiation ensures both seal durability and corrosion resistance.
Solution Approach 2:
The primer coating layer acts as an intermediary between the metal separator and the main resin coating layer, facilitating strong bonding and preventing direct contact that would cause delamination. This intermediary layer ensures long-term seal durability.
3Manufacturing precision
If electrodeposition is used to form a uniform resin coating, then coating uniformity is improved, but adhesion to counterpart members deteriorates due to lack of surface roughness
Solution Approach 1:
The primer layer is applied in advance to create an adhesive foundation before the uniform resin coating is deposited. This preliminary action ensures that the smooth, uniform coating maintains strong adhesion to the separator through the primer's anchoring effect.
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 increased surface roughness of the resin coating layer enhances anchoring effects, significantly improving adhesion and durability, reducing the likelihood of delamination and ensuring high seal durability over time.
Implementation Method 1
The resin coating layer is formed by, for example, electrodepositing a cationic resin, which has been obtained by ionizing resin powder such as epoxy resin, urethane resin, acrylic resin, or polyimide resin, on the surface of the separator.
Implementation Method 2
the surface of the resin coating layer has been subjected to shot blasting or the like
Data Source
AI summary
A fuel cell separator 60 having a metal plate and an anticorrosion resin coating layer 55 formed thereon is provided, with which adhesion between the resin coating layer 55 and its counterpart member is further increased and the durability of a fuel cell unit is improved. In forming the fuel cell separator 60 having a separator substrate 50 that is a metal plate and an anticorrosion resin coating layer 55 formed thereon, the resin coating layer 55 is formed such that it has a surface roughness Ra of 0.5 to 13.5 μm. Increasing the surface roughness will produce an anchoring effect, which will improve the adhesive force at the interface. The aforementioned surface roughness Ra can be obtained either with the use of fillers that are mixed into the resin coating layer 55 or with external force applied to the surface of the resin coating layer 55 by means of shot blasting, for example.