Fuel Cell Stack Separator Overlap for Sealing Force Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In fuel cell stacks, the reaction force of sealing members can cause separators to bend inward, narrowing gas channels and decreasing sealing surface pressure, which is a problem that existing technologies have not effectively addressed.
Innovation Solution
The fuel cell stack design includes separators with supporting portions of different sizes, forming overlapped areas that receive and transmit the reaction force of sealing members between single cells, preventing channel narrowing and pressure decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing members are disposed between adjacent cells to prevent fluid leakage, then sealing performance is improved, but reaction force from sealing members causes separators to bend inward narrowing gas channels
Solution Approach 1:
A reaction force receiving structure is introduced as an intermediary component between the sealing member and the separator. This structure receives the reaction force from the sealing member and transmits it to the frame, preventing the force from acting directly on the separator and causing inward bending. The intermediary structure thus protects the gas channel shape while maintaining sealing effectiveness.
Solution Approach 2:
The reaction force receiving structure provides a counterbalancing mechanism that opposes the inward bending force exerted by the sealing member on the separator. By providing this counteracting support, the structure prevents the separator from deforming inward, thereby maintaining the gas channel width despite the presence of tight sealing members.
2Reliability
If sealing members are disposed between adjacent cells to prevent fluid leakage, then sealing performance is improved, but sealing surface pressure decreases due to separator deformation
Solution Approach 1:
The reaction force receiving structure serves as a mediator that decouples the sealing function from the structural support function. By receiving and transmitting the reaction force to the frame, it prevents separator deformation that would otherwise reduce sealing surface pressure, thereby maintaining both sealing performance and adequate contact pressure.
Solution Approach 2:
The reaction force receiving structure provides preliminary support to the separator before the sealing member can cause significant deformation. This preemptive support prevents the separator from bending inward, ensuring that the sealing surface pressure is maintained at appropriate levels throughout operation.
3Length of moving object
If separators are made thinner to reduce cell thickness, then compactness is improved, but separators become more susceptible to bending from sealing member reaction force
Solution Approach 1:
The reaction force receiving structure acts as a protective intermediary that shields thin separators from the full impact of sealing member reaction forces. This allows the use of thinner, more compact separators without compromising their structural integrity, as the receiving structure absorbs and redirects the bending forces.
Solution Approach 2:
The reaction force receiving structure provides beforehand cushioning support to thin separators, preventing them from experiencing excessive bending stresses. This cushioning effect enables the use of thinner separators by pre-comparing them against the reaction forces that would otherwise cause deformation.
Data Source
AI summary
The fuel cell stack FS includes; a stacked plurality of single cells C each including a frame 1 of a membrane electrode assembly 2 and a pair of separators 3, 4; and a sealing member 6 disposed between the plurality of single cells C. The pair of separators 3, 4 include respective supporting portions 9, 10 that are in contact with the frame 1, and the sealing member 6 is disposed on one supporting member 10. Further, the supporting portions 9, 10 of the separators 3, 4 have different sizes so that an overlapped portion W is formed in which a base surface 7 where the supporting portion 9 of one separator 3 is in contact with the frame 1 is overlapped with a top surface 8 where the supporting portion 10 of the other separator 4 is in contact with the frame 1 in the stacking direction. The overlapped portion W receives and transmits reaction force of the sealing member 6 between the single cells, which prevents narrowing of gas channels or decrease of the sealing surface pressure.