Fuel Cell Stack Mounting Hole Chamfer Design
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Solution Overview
Problem
Conventional fuel cell stacks experience gas leakage and water ingress, leading to corrosion and seal member damage due to the small molecule size of hydrogen gas and the design of mounting holes, which compromises the integrity of the fuel cell stack.
Innovation Solution
The fuel cell stack incorporates a dual seal system with chamfered parts on the mounting holes and a cylindrical knock, where the first seal member contacts the inner surface of the end plate mounting hole and the second seal member contacts the connection bar mounting hole, preventing gas leakage and water ingress, while the chamfered angles and diameters are optimized to minimize seal member damage during assembly and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member is attached to the mounting hole to prevent gas leakage and water ingress, then sealing performance is improved, but the seal member may be damaged during assembly or maintenance when contacting sharp corners
Solution Approach 1:
Chamfered parts are formed on the mounting hole before the seal member is installed. This preliminary structural preparation creates a protective beveled surface that prevents the seal member from contacting sharp corners during assembly and maintenance operations, thereby avoiding damage while ensuring proper sealing contact surfaces are established in advance
Solution Approach 2:
The chamfered part acts as an intermediary protective structure between the sharp corner of the mounting hole and the seal member. It provides a gradual transition surface that redirects contact away from the vulnerable seal member during installation and maintenance, serving as a buffer that preserves seal integrity
2Ease of manufacture
If the mounting hole design is simple, then manufacturing is easier, but gas leakage and water ingress occur through the mounting hole
Solution Approach 1:
The mounting hole is segmented into multiple functional zones: the through-hole portion for fastener passage and the chamfered part for sealing. This segmentation allows the simple cylindrical through-hole to be combined with the added chamfered sealing surface, maintaining ease of manufacture for the base structure while adding sealing capability through a relatively simple machining operation
Solution Approach 2:
The chamfered part is applied locally at the opening edge of the mounting hole rather than modifying the entire hole structure. This localized modification provides the necessary sealing surface while minimizing additional manufacturing complexity, concentrating the sealing function at the critical interface where the seal member contacts the mounting hole
Data Source
AI summary
Provided is a fuel cell stack capable of suppressing damage to a seal member and suppressing leakage of a reaction gas to the outside of a casing or entry of water from the outside of the casing for a long period of time. The fuel cell stack includes a pair of end plates and holds a laminate from two sides in a direction, a casing which houses the laminate and has connection bars extended between the pair of end plates, a fastening member inserted into an end plate side mounting hole and a connection bar side mounting hole, and chamfered parts formed in an end plate side small diameter part of the end plate side mounting hole. A chamfer angle between an inner surface of the outer chamfered part and the direction is larger than a chamfer angle between an inner surface of the inner chamfered part and the direction.