Fuel Cell Stack Porous Cover Geometry for Hydrogen Venting
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Solution Overview
Problem
In fuel cell systems, conductors extending from cell voltage detection terminals can block ventilation openings in the porous cover, preventing hydrogen gas from being discharged outside the stack case, and may also be damaged by burrs formed during manufacturing.
Innovation Solution
A fuel cell system design featuring a porous cover with an annular protrusion on its end face, which contacts the conductor from the cell voltage detection terminal, preventing blockage of ventilation holes and avoiding damage to the conductor by gentle curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductor extends from the cell voltage detection terminal without obstruction, then the conductor may block the ventilation through-holes of the porous cover, but providing an annular protrusion to prevent blockage may cause damage to the conductor through sharp edges
Solution Approach 1:
The annular protrusion is designed with curved surfaces instead of sharp edges. The inner peripheral side surface and top surface are continuous via an inner curved portion, and the outer peripheral side surface and top surface are continuous via an outer curved portion. This curvature prevents the conductor from being caught or damaged by sharp edges while still effectively blocking the conductor from obstructing the ventilation through-holes.
2Ease of manufacture
If the ventilation cover is made of resin material and manufactured by injection molding, then the manufacturing process is simple and cost-effective, but burrs are formed on the portion pressed by the ejector pin which may damage the conductor
Solution Approach 1:
The annular protrusion features curved surfaces with continuous transitions between the top surface and peripheral side surfaces. These curved surfaces prevent burrs formed during injection molding from catching or damaging the conductor, as the smooth curved geometry eliminates sharp edges where burrs could form or where the conductor could be snagged.
Solution Approach 2:
The curved surfaces of the annular protrusion serve as a protective feature built into the design before the conductor is installed. This pre-designed curvature cushions against potential conductor damage from burrs that may form during the injection molding process, preventing harm before it occurs.
3Reliability
If the annular protrusion has sharp edges to effectively block the conductor, then the ventilation function is maintained, but the conductor may be caught and damaged by the sharp portion
Solution Approach 1:
The annular protrusion is designed with continuously curved surfaces where the inner peripheral side surface and outer peripheral side surface are each continuous with the top surface via curved portions. This curvature maintains the protrusion's ability to block the conductor from reaching the ventilation through-holes while eliminating sharp edges that could catch or damage the conductor, thus preserving conductor integrity.
Data Source
AI summary
An opening is formed at an end portion of a stack case that houses a fuel cell stack. A unit cell constituting a fuel cell stack is provided with a cell voltage detection terminal at a position facing an opening. A conductor extends from the cell voltage detection terminal. The opening is covered with a porous cover that is formed with a plurality of through-holes. The porous cover is formed with an annular protrusion on an end face facing the cell voltage detection terminal. The annular protrusion is located among the plurality of through-holes.