Fuel Cell Separator Bosses for Uniform Flow
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Solution Overview
Problem
In fuel cells, the use of thin metal separators to reduce size and weight results in constrained coolant flow fields, leading to non-uniform coolant flow rates due to the inevitable shaping of reactant and coolant flow fields on both surfaces, which affects the distribution and flow of gases and coolant.
Innovation Solution
The fuel cell design incorporates first and second metal plates with reactant gas and coolant buffers featuring bosses on opposite surfaces, allowing for separate and non-overlapping reactant and coolant buffer structures, enabling uniform flow fields and proper distribution of gases and coolant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a thin metal separator is used to reduce the overall size and weight of the fuel cell, then the weight and size are reduced, but the coolant flow field shape is significantly constrained leading to non-uniform coolant flow rate
Solution Approach 1:
The separator is divided into multiple functional regions: reactant gas flow fields on the electrode-facing surfaces, coolant flow fields on the opposite surfaces, and buffer regions positioned between them. This segmentation allows each region to be optimized independently, enabling uniform coolant flow distribution while maintaining thin separator structure.
Solution Approach 2:
The buffer regions extend in the stacking direction (thickness dimension) to provide sufficient space for both reactant gas and coolant flow fields. By utilizing the thickness dimension effectively, the patent achieves desired flow field heights and uniformity without increasing the planar dimensions, thus maintaining reduced size and weight.
2Manufacturing precision
If the reactant gas flow field comprises serpentine flow grooves extending along the electrode surface, then the gas distribution is improved, but the shape of the coolant flow field is significantly constrained
Solution Approach 1:
The separator is divided into multiple functional regions: reactant gas flow fields on the electrode-facing surfaces, coolant flow fields on the opposite surfaces, and buffer regions positioned between them. This segmentation allows each region to be optimized independently, enabling uniform coolant flow distribution while maintaining thin separator structure.
Solution Approach 2:
Different regions of the separator are given different functions and structures: serpentine grooves in reactant gas flow fields for optimal gas distribution, straight or curved channels in coolant flow fields for uniform cooling, and buffer regions for structural support and flow management. Each region's structure is optimized for its specific function.
3Area of stationary object
If buffers of three kinds of fluid (oxygen-containing gas, fuel gas, and coolant) are overlapped in the stacking direction, then the cross-sectional area requirements are met, but the desired height of the flow field is not achieved and fluids are not distributed smoothly
Solution Approach 1:
The buffer regions extend in the stacking direction (thickness dimension) to provide sufficient space for both reactant gas and coolant flow fields. By utilizing the thickness dimension effectively, the patent achieves desired flow field heights and uniformity without increasing the planar dimensions, thus maintaining reduced size and weight.
Solution Approach 2:
The separator is divided into multiple functional regions: reactant gas flow fields on the electrode-facing surfaces, coolant flow fields on the opposite surfaces, and buffer regions positioned between them. This segmentation allows each region to be optimized independently, enabling uniform coolant flow distribution while maintaining thin separator structure.
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 achieves the desired height and uniformity in reactant and coolant flow fields, ensuring smooth flow and appropriate load distribution, thereby enhancing the fuel cell's performance and efficiency.
Implementation Method 1
The catalyst of the anode induces a chemical reaction of the fuel gas to split the hydrogen molecule into hydrogen ions and electrons
Implementation Method 2
The hydrogen ions move toward the cathode through the electrolyte
Implementation Method 3
The hydrogen ions move toward the cathode through the electrolyte, and the electrons flow through an external circuit to the cathode, creating a DC electrical energy
Implementation Method 4
a coolant flows along the surfaces of the separators
Data Source
AI summary
A fuel cell includes a membrane electrode assembly and separators sandwiching the membrane electrode assembly. Each of the separators includes first and second metal plates. When the fist and second metal plates are stacked together, an inlet buffer and an outlet buffer are overlapped with each other in the stacking direction. A plurality of bosses in the inlet buffer and a plurality of bosses in the outlet buffer are not overlapped with each other.