Fuel Cell Separator Turn Portion Stagnation Reduction
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Solution Overview
Problem
In fuel cell separators, reactant gas and condensed water tend to stagnate at turn portions, leading to increased electrical contact resistance between the separator and the electrode.
Innovation Solution
A fuel cell separator with a plate shape featuring groove-like straight portions and turn portions, including gas mixing and separating portions with depressed areas and protruding elements, designed to facilitate gas flow and reduce stagnation, with rib structures that guide gas flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the separator uses conventional serpentine channels with turn portions, then the gas flow path is continuous, but reactant gas and condensed water stagnate at the turn portions
Solution Approach 1:
The turn portion is segmented into three functional sections: gas meeting portion, gas mixing portion, and gas separating portion. This segmentation allows the gas flow to be systematically managed through each section, preventing stagnation while maintaining continuous flow. The depressed portion further divides the mixing section to enhance flow dynamics.
Solution Approach 2:
The outer peripheral portion of the turn portion is designed with a curved shape that is rounded rather than sharp. This curvature prevents dead zones where gas and water could stagnate, ensuring smooth flow transitions through the turn portion while maintaining continuous gas supply.
2Reliability
If the separator increases contact area with electrode to reduce contact resistance, then electrical contact resistance decreases, but the complexity of groove configuration increases
Solution Approach 1:
Different sections of the separator have different groove configurations optimized for their specific functions. The turn portion has the complex three-section design for flow management, while other areas maintain simpler patterns. This localized optimization reduces overall complexity while achieving low contact resistance where needed.
Solution Approach 2:
The groove structure serves multiple functions simultaneously: it guides gas flow through the turn portion, prevents stagnation, maintains electrical contact with the electrode, and manages condensed water removal. This multi-functionality reduces the need for additional separate components, simplifying the overall design.
Data Source
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AI summary
A fuel cell separator of the present invention is provided with a reactant gas flow region (8) including a plurality of straight portions (11) and one or more turn portions (12). At least one of one or more turn portions (12) includes a gas mixing portion (12b), a gas meeting portion (12a), and a gas separating portion (12c). Second rib portions (14) are formed in the gas meeting portion (12a) and the gas separating portion (12c). The second rib portions (14) are formed such that the length of an inner second rib portion (14) is shorter than the length of an outer second rib portion (14) in a direction in which the second rib portions (14) extend. An outermost second rib portion (141) located farthest from a center rib portion (13A) is formed so as to be bent inward toward the center line (131).