Fuel Cell Separator Seal Structure for Fluctuating Gaps
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Solution Overview
Problem
Existing seal structures for fuel cell separators face challenges in following gap fluctuations due to temperature changes without generating excessive tightening force, which can lead to peeling or breakage, especially when using brittle materials like carbon.
Innovation Solution
A seal structure featuring beads with a rubber-like elastic material interposed between the separators, allowing for nested overlap and using a seal material with stickiness or adhesiveness to maintain a fluid seal without large compressive forces, enabling the seal material to deform shearingly and accommodate gap changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a seal structure using gaskets with rubber-like elastic material is used, then tightening force is strong, but it is not suitable for brittle separators and may cause breakage
Solution Approach 1:
The patent uses a gasket made of flexible rubber-like elastic material that can deform to accommodate gap fluctuations between separators. The gasket acts as a flexible element that absorbs dimensional changes without transmitting excessive force to the brittle separator, thus preventing breakage while maintaining sealing effectiveness.
Solution Approach 2:
The patent specifies that the rubber-like elastic material should have a JIS A hardness of 50 to 90 degrees, optimizing the balance between flexibility and structural integrity. This parameter control ensures the gasket is soft enough to follow gap fluctuations but firm enough to provide adequate sealing force without being too soft to maintain shape.
2Force
If a seal structure using adhesive seals or sticking seals is used, then tightening force is low, but it cannot follow gap fluctuations and may cause peeling off or breakage
Solution Approach 1:
The patent employs a dynamic sealing approach where the gasket can elastically deform in response to changing gap dimensions. Unlike static adhesive seals, the gasket continuously adapts its shape to follow gap fluctuations caused by thermal expansion and contraction, maintaining sealing contact without peeling off the separator surface.
Solution Approach 2:
The gasket is designed as a flexible component that can bend and deform to accommodate dimensional changes in the separator assembly. This flexibility allows the seal to track gap variations dynamically, preventing the peeling and breakage issues associated with rigid adhesive seals.
3Reliability
If a seal structure is used that generates large tightening force, then sealing is strong, but it causes peeling or breakage in brittle separators
Solution Approach 1:
The gasket serves as a compliant sealing element that provides adequate sealing force through its elastic properties rather than through high compressive loads. The flexibility of the rubber-like material allows it to conform to the separator surface and maintain sealing pressure without generating the large tightening forces that would damage brittle separators.
Solution Approach 2:
The patent optimizes the gasket material hardness to a JIS A value of 50-90 degrees, creating a parameter window where the seal is soft enough to avoid damaging the separator yet firm enough to provide reliable sealing. This controlled hardness parameter prevents excessive tightening force while maintaining sealing effectiveness.
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 configuration allows the seal to follow gap fluctuations without generating large tightening forces, ensuring a reliable seal even with brittle separators, preventing peeling or breakage and maintaining effective fluid separation.
Implementation Method 1
a seal provided with a seal material having elasticity between side walls of the beads of the pair of separators
Implementation Method 2
it is strong in tightening force and is not suitable for application to the brittle separator
Data Source
AI summary
A seal structure is provided that follows fluctuations in a gap between a pair of fuel cell separators without generating a large tightening force. A pair of separators facing each other with an electrolyte membrane as a mating member interposed therebetween have beads which form a flow path for fluid between the beads and the electrolyte membrane in close contact with the electrolyte membrane. A seal which seals the pair of separators causes the beads 14 of the pair of these separators to overlap each other in a nested manner. A seal material having elasticity is provided between side walls of the respective beads which face each other. When the gap between the pair of separators fluctuates, the seal material deforms in a shearing direction.