Fuel Cell Separator Rib Design for Uniform Sealing Pressure
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Solution Overview
Problem
Fuel cell stacks face challenges in maintaining consistent bearing pressure on the sealing portion due to the high rigidity of load receiving portions, which can lead to variations in pressure distribution and potential movement of unit cells during external impacts.
Innovation Solution
Incorporating ribs on the separator that protrude between the sealing and load receiving portions, with openings at the ends to reduce rigidity and allow bending, thereby maintaining consistent pressure on the sealing portion and enhancing the overall rigidity of the supporting structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rib is formed to protrude from the separator between the sealing portion and the load receiving portion toward the opposite separator, then the rigidity of the supporting portion is increased, but the bearing pressure on the sealing portion becomes uneven due to the high rigidity of the rib ends
Solution Approach 1:
The patent applies local quality by creating a rigidity gradient along the rib structure. The rib has different rigidity characteristics at different locations: the root portion maintains high rigidity for structural support, while the end portion has reduced rigidity (through openings or reduced thickness) to allow bending and maintain uniform bearing pressure distribution on the sealing portion.
Solution Approach 2:
The patent changes the physical parameters of the rib structure by introducing openings or varying the thickness along the rib length. This parameter change allows the rib to transition from a uniformly rigid structure to one with spatially varying rigidity, enabling both structural support and uniform pressure distribution.
2Strength
If the rib ends are made highly rigid to support the load receiving portion, then the supporting strength is improved, but the sealing performance deteriorates due to pressure loss at the sealing portion
Solution Approach 1:
The rib structure implements local quality by having different mechanical properties at different locations. The root portion near the separator maintains high strength for structural support, while the end portion near the sealing area has reduced rigidity to allow bending, ensuring uniform pressure distribution and maintaining sealing performance.
Solution Approach 2:
The patent introduces dynamic characteristics to the rib structure by allowing the end portion to bend under load. This dynamic behavior enables the rib to adapt to variations in assembly conditions and maintain consistent sealing pressure, rather than acting as a completely rigid structure.
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 design increases the rigidity of the supporting portions while allowing the ribs to effectively bend under tightening loads, reducing pressure variations on the sealing portion and enhancing the stability of the fuel cell stack.
Implementation Method 1
a rib protruding from the separator at a portion between the sealing portion and the load receiving portion toward the opposite separator and extending in a line along an extending direction of the sealing portion
Implementation Method 2
the rib ends in the extending direction thereof are hard to bend because of relatively high rigidity. Thus, the tightening load of the fuel cell stack acts on the rib ends
Data Source
AI summary
A first separator constituting a separator member of a fuel cell stack is provided with a first rib that protrudes from the first separator at a portion between a first seal line and a load receiving portion toward a second separator located on the opposite side across an MEA and that extends in a line along the extending direction of the first seal line. An opening is formed in at least one end of the first rib in the extending direction thereof.