Cross-Flow Fuel Cell Centroid Positioning for Temperature Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fuel cell stacks face challenges in achieving uniform in-plane temperature distribution, leading to thermal stress, cracking, and reduced durability and output voltage over time, despite attempts to improve temperature uniformity through gas flow direction alterations.
Innovation Solution
A planar fuel cell apparatus with a cross-flow design where the centroids of fuel gas and oxidizer gas inlets and outlets are strategically positioned to ensure overlapping high-temperature fuel and low-temperature oxidizer gas regions, enhancing temperature uniformity across the fuel cell surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gas flow direction arrangements are used in fuel cell stacks, then the structure is simple, but the cell in-plane temperature distribution becomes nonuniform leading to thermal stress and reduced durability
Solution Approach 1:
The patent applies asymmetry by positioning the fuel gas outlet centroid closer to the oxidizer gas inlet centroid than to the oxidizer gas outlet centroid. This asymmetric arrangement creates overlapping regions where hot fuel gas and cold oxidizer gas mix, generating diagonal temperature gradients that uniformize the cell in-plane temperature distribution and reduce thermal stress, thereby improving durability without requiring complex multi-tier configurations
Solution Approach 2:
The patent introduces a new design dimension by focusing on the relative positional relationships between gas flow centroids rather than simply reversing flow directions in different tiers. This dimensional approach to flow channel configuration enables temperature uniformization through strategic centroid positioning, offering a novel solution that avoids the complexity of conventional multi-tier alternating flow designs
2Temperature
If gas flow directions are reversed tier by tier to uniformize temperature, then temperature distribution improves somewhat, but sufficient uniformity is not achieved and thermal stress remains
Solution Approach 1:
The patent employs asymmetry in the relative positioning of gas flow centroids to create diagonal temperature gradients. Specifically, positioning the fuel gas outlet centroid closer to the oxidizer gas inlet centroid generates overlapping hot and cold gas regions that produce temperature uniformization effects, effectively reducing thermal stress and achieving both temperature uniformity and thermal stress resistance simultaneously
3Productivity
If cross-flow design with orthogonal fuel and oxidizer gas channels is used, then gas flow efficiency is improved, but cell in-plane temperature distribution becomes nonuniform in some cases
Solution Approach 1:
The patent modifies the conventional symmetric cross-flow design by introducing asymmetric positioning of gas flow centroids. The fuel gas outlet centroid is positioned closer to the oxidizer gas inlet centroid than to the oxidizer gas outlet centroid, creating diagonal temperature gradients that uniformize the cell in-plane temperature distribution while preserving the electricity generation efficiency of the cross-flow configuration
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 improves durability and maintains high electricity generation capability by achieving uniform in-plane temperature distribution, even in stacks with poor thermal conduction between adjacent cells, and enhances the compatibility between output voltage and durability.
Implementation Method 1
a solid electrolyte layer sandwiched therebetween
Implementation Method 2
an anode layer, a cathode layer, and a solid electrolyte layer sandwiched therebetween
Implementation Method 3
a first rectilinear line which connects a centroid Cfi of the fuel gas inlet(s) and a centroid Cfo of the fuel gas outlet(s), and a second rectilinear line which connects a centroid Cai of the oxidizer gas inlet(s) and a centroid Cao of the oxidizer gas outlet(s) cross each other
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
Provided is a planar fuel cell apparatus capable of uniformizing the planar temperature of a single fuel cell (i.e., cell in-plane temperature). The planar fuel cell apparatus 1 is such that, as viewed in a stacking direction, a first rectilinear line which connects a centroid Cfi of fuel gas inlets and a centroid Cfo of fuel gas outlets, and a second rectilinear line which connects a centroid Cai of oxidizer gas inlets and a centroid Cao of oxidizer gas outlets cross each other. That is, the planar fuel cell apparatus employs cross-flow design in which a fuel gas flow channel and an oxidizer gas flow channel cross each other. In the planar fuel cell apparatus of the cross-flow design, as viewed in the stacking direction, the centroid Cfo of the fuel gas outlets is located closer to the centroid Cai of the oxidizer gas inlets than to the centroid Cao of the oxidizer gas outlets.