Fuel Cell Separator With Variable Cross-Sectional Channels
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Solution Overview
Problem
In air-cooled fuel cells, the temperature gradient along the channels leads to drying of the membrane electrode assembly on the outlet side, reducing power generation performance due to inadequate cooling and increased resistance.
Innovation Solution
The fuel cell design incorporates a cathode-side separator with power-generation channels and cooling channels of varying cross-sectional areas, separated by a side wall with through-holes, allowing air to flow from power-generation channels into cooling channels, thereby maintaining optimal cooling and reducing drying of the membrane electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air cooling method is used to cool the fuel cell, then cooling effect is achieved, but temperature gradient appears along the channel causing drying of membrane electrode assembly on outlet side
Solution Approach 1:
The patent applies local quality by varying the cross-sectional area of the cooling channel along its length. The cross-sectional area is smaller at the inlet side and larger at the outlet side, creating different flow characteristics and cooling intensities at different locations. This non-uniform design compensates for the temperature gradient, providing enhanced cooling at the outlet side where drying occurs, while maintaining appropriate cooling at the inlet side.
Solution Approach 2:
The patent changes the geometric parameter of the cooling channel (cross-sectional area) along its length to optimize cooling distribution. By increasing the cross-sectional area toward the outlet side, the air flow rate and cooling capacity are adjusted to match the heat generation distribution, thereby preventing excessive temperature rise and membrane drying at the outlet.
2Ease of operation
If through-hole is provided in side wall to connect power-generation channel and cooling channel, then air flow between channels is enabled, but channel structure becomes more complex
Solution Approach 1:
The through-hole acts as an intermediary connection between the power-generation channel and the cooling channel. It enables controlled air flow exchange between the two channels, allowing excess air from the power-generation channel to enter the cooling channel and enhance cooling efficiency, while maintaining structural integrity and simplicity.
Solution Approach 2:
The side wall with through-hole serves multiple functions: it separates the power-generation channel and cooling channel while simultaneously providing a controlled connection for air flow. This multi-functional design enables both channel isolation and inter-channel communication without requiring additional complex components.
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 curbs the reduction in power generation performance by ensuring effective cooling and minimizing the drying of the membrane electrode assembly, maintaining efficient power generation across the fuel cell.
Implementation Method 1
an air cooling method in which oxidant gas supplied for use in electric power generation is used for cooling
Implementation Method 2
the temperature of oxidant gas that flows through a channel rises due to heat generated by electrochemical reactions in the membrane electrode assembly
Data Source
AI summary
A fuel cell includes a power-generation channel provided on a surface of a cathode-side separator which faces a MEA and a cooling channel provided on a surface of the cathode-side separator opposite to the MEA. Air flows through the power-generation channel and the cooling channel. The cooling channel is separated from the power-generation channel by a side wall. The cross-sectional area of the power-generation channel on the air outlet side is smaller than that of the power-generation channel at a position upstream of the air outlet side, and the cross-sectional area of the cooling channel on the air outlet side is larger than that of the cooling channel at a position upstream of the air outlet side. A through-hole is provided in a side wall that separates the power-generation channel from the cooling channel.