Fuel Cell Unit Cell Sheet Structure for Uniform Pressure Sealing
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Solution Overview
Problem
Existing fuel cell stacks face challenges in maintaining uniform surface pressure and preventing deformation of separators when a large number of fuel cells are stacked, while also ensuring airtightness and efficient gas flow.
Innovation Solution
A unit cell design for fuel cell stacks that includes a sheet with an insertion groove for an electricity-generating assembly (EGA), coupled with first and second separators that have reaction flow fields and are secured by gaskets on both sides of the second separator, facilitating uniform pressure and airtightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large number of fuel cells are stacked, then the power output increases, but the separators deform and surface pressure becomes non-uniform
Solution Approach 1:
A sheet is introduced as an intermediary component between the first and second separators. This sheet includes a through hole that forms a flow path for reaction gases and helps maintain uniform surface pressure distribution across the stacked fuel cells, preventing separator deformation while allowing increased stacking for higher power output
Solution Approach 2:
The flow path for reaction gases is segmented into multiple channels by dividing it into a first gas flow field and a second gas flow field. This segmentation is achieved by positioning the through hole in the sheet at a point spaced apart from the second gas flow field, creating distinct flow regions that improve gas distribution and pressure uniformity across the stack
2Power
If a large number of fuel cells are stacked, then the power output increases, but uniform surface pressure cannot be maintained
Solution Approach 1:
The sheet acts as a pressure-distributing intermediary between separators. The through hole in the sheet creates a controlled flow path that equalizes pressure distribution across the stack, maintaining uniform surface pressure even when many fuel cells are stacked for higher power output
3Reliability
If gaskets are provided on both sides of the second separator, then airtightness is improved, but the complexity of the assembly increases
Solution Approach 1:
The sheet is integrated with the second separator assembly, combining multiple functions into a single structured component. The sheet includes both the through hole for gas flow and works in conjunction with gaskets to provide airtightness, reducing the number of separate components needed while maintaining reliability
Data Source
AI summary
An embodiment unit cell of a fuel cell stack includes an EGA in which a MEA and a GDL are bonded, a sheet including an insertion groove and a through hole for flowing a gas therethrough, wherein the EGA is insertable into the insertion groove, a first separator coupled to the sheet and including a first reaction flow field through which a first gas flows on a first side of the first separator, and a second separator coupled to the sheet and including a second reaction flow field through which a second gas flows on a first side of the second separator, a second gas flow field connected to a first or second end of the second reaction flow field, and a first gas flow field connected to the first reaction flow field through the through hole disposed at a point spaced apart from the second gas flow field.