Fuel Cell Case Anodic Oxide Coating Corrosion
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Solution Overview
Problem
Fuel cell modules are prone to corrosion due to water remaining in crevices between the case and seal members, leading to potential damage and inefficiency.
Innovation Solution
The application of an anodic oxide coating with enhanced rust and wear resistance on surfaces of the case, particularly in areas where water tends to accumulate, such as grooves and press-fitting holes, along with sealing the coating to improve rust resistance and prevent adhesive friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water enters the crevice between the case and seal member, then the case is exposed to corrosion, but forming an anodic oxide coating on the case surface increases manufacturing complexity
Solution Approach 1:
The anodic oxide coating is formed on the case surface before assembly with the seal member, creating a protective layer in advance that prevents corrosion when water enters the crevice. This preliminary protective action eliminates the need for complex post-assembly corrosion protection measures.
Solution Approach 2:
The case is formed as a composite structure combining aluminum base material with an anodic oxide coating layer. This composite material provides both the structural properties of aluminum and the enhanced corrosion resistance of the oxide coating, solving the reliability issue without requiring complex external protection systems.
2Weight of moving object
If aluminum or aluminum alloy is used for the case, then weight is reduced, but corrosion resistance is insufficient when water remains in crevices
Solution Approach 1:
The aluminum case is combined with an anodic oxide coating to create a composite material structure. The aluminum provides lightweight properties while the oxide coating provides enhanced corrosion resistance, simultaneously satisfying both weight reduction and reliability requirements.
Solution Approach 2:
The surface properties of the aluminum case are changed through anodizing, which transforms the surface chemistry and structure to create a more corrosion-resistant anodic oxide layer while maintaining the bulk aluminum's lightweight characteristics.
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
Effectively suppresses corrosion and prevents electric leakage by forming a durable, insulating barrier against water, enhancing the longevity and performance of the fuel cell module, especially when installed below a vehicle's floor where water splashing is likely.
Implementation Method 1
As a rust-proof treatment for aluminum or the aluminum alloy, the effect of an anodizing treatment is high. According to the above configuration, since the anodic oxide coating having rust resistance higher than those of aluminum and the aluminum alloy is formed on the surface
Implementation Method 2
since the anodic oxide coating having an insulating property higher than those of aluminum and the aluminum alloy is formed on the surface inside the case, in the case where the high-voltage portion comes into contact with the surface on which the anodic oxide coating is formed inside the case, it is possible to prevent an electric leakage from the high-voltage portion to the case
Data Source
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AI summary
A fuel cell module is disposed below a floor of a vehicle (10). The fuel cell module includes: a high-voltage portion including a fuel cell (110); a case (120) that is formed of aluminum or aluminum alloy and that accommodates at least a part of the high-voltage portion; and a gasket (160) sandwiched between the case (120) and another component (170), which is different from the case (120). An anodic oxide coating is formed on at least a surface that comes into contact with the gasket (160) in a surface of the case (120).