Separator Groove Depth Uniformity for Fuel Cell Press Forming
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Solution Overview
Problem
Conventional fuel cell separators face challenges in maintaining material elongation accuracy and preventing breakage or deformation due to differences in groove depths during press working, particularly at orthogonal corners where deep and shallow groove portions are adjacent.
Innovation Solution
A separator design with a recess-projection shape featuring a reactive gas turn portion of constant depth and a non-angular smooth curve, facilitating consistent material elongation and reducing the risk of breakage or deformation by maintaining groove depth uniformity at turn portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If deep groove portion and shallow groove portion are formed adjacent to each other at orthogonal corner of turn portion, then cooling water flow path and reactive gas flow path can be formed, but material elongation accuracy deteriorates and breakage or deformation occurs easily
Solution Approach 1:
The invention applies local quality by making the reactive gas flow path groove depth variable: deep groove portions are positioned away from orthogonal corners where turn portions exist, while shallow groove portions are positioned at or near orthogonal corners. This local differentiation ensures that grooves near turn portions do not cause excessive material elongation that would lead to breakage or deformation, while still maintaining effective cooling water flow paths.
Solution Approach 2:
The invention segments the reactive gas flow path grooves into different depth regions: deep groove portions located away from turn portions and shallow groove portions located at or near orthogonal corners. This segmentation allows each region to serve its specific function - deep grooves for effective gas flow distribution and shallow grooves for preventing material failure at stress-prone turn portion areas.
2Reliability
If shallow groove portion is formed at reactive gas flow path groove near turn portion, then material breakage is reduced, but die machining difficulty increases
Solution Approach 1:
The die is designed with local quality by providing different groove depth forming capabilities at different regions. The die includes a first groove forming portion for forming deep grooves and a second groove forming portion for forming shallow grooves, with the second portion specifically configured to form grooves with smaller depth at orthogonal corners where turn portions are located.
Solution Approach 2:
The die structure is segmented into multiple groove forming portions with different functional characteristics. By dividing the die into regions that form deep grooves and regions that form shallow grooves, the invention simplifies the overall die design while achieving the desired variable groove depth pattern in the separator.
3Ease of manufacture
If constant depth groove is used throughout, then die machining is simplified, but material elongation varies causing breakage or deformation
Solution Approach 1:
The invention applies local quality by positioning shallow groove portions specifically at orthogonal corners where turn portions of the reactive gas flow path are located, while deep groove portions are positioned away from these corners. This localized depth variation prevents excessive material elongation at critical turn portion areas, maintaining structural integrity without requiring complex variable-depth die designs throughout the entire separator.
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 enhances the accuracy and reliability of the separator's shape during press working, reducing the likelihood of breakage or deformation and improving the efficiency of cooling water distribution while minimizing contact resistance and maintaining maximum fuel cell output.
Implementation Method 1
a recess-projection shape formed by press working
Data Source
AI summary
A separator has a recess-projection shape formed by press working. The separator has one surface as a gas circulation surface and an opposite surface as a cooling surface, the gas circulation surface having a reactive gas flow path including a plurality of reactive gas flow path grooves resulting from the recess-projection shape, the cooling surface having a cooling water flow path including a plurality of cooling water flow path grooves resulting from the recess-projection shape. The cooling water flow path includes an intersection flow path portion including cooling water flow path grooves adjacent to each other with a reactive gas flow path groove of the reactive gas flow path therebetween, and a communication flow path groove formed at the cooling surface side of the reactive gas flow path groove between the adjacent cooling water flow path grooves, the communication flow path groove being shallower than the cooling water flow path grooves; and a cooling water turn portion where a direction of the cooling water flow path grooves changes. A reactive gas turn portion is formed at the gas circulation surface in a position on the rear side of the cooling water turn portion, and the reactive gas turn portion is formed of a groove portion having a constant depth.