Fuel Cell Stack Porous Separator Layout for Membrane Hydration
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Solution Overview
Problem
Solid polymer fuel cell stacks face deterioration due to low humidity and high temperatures, leading to insufficient reactants and carbon corrosion, which results in unstable operation and cell degradation.
Innovation Solution
A fuel cell stack design with a differential pressure management system, where the cooling water pressure is lower than the fuel gas pressure, and the pressure difference between the fuel gas and cooling water is maintained to prevent drying and retain condensed water, using porous separators with hydrophilic micropores to absorb and humidify gases effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high flow rate gas is supplied to the cell stack, then productivity is improved, but the humidity at gas inlet decreases and the stack becomes dry
Solution Approach 1:
The gas is humidified before being supplied to the fuel cell stack by passing it through a humidifier where water is introduced to increase humidity. This preliminary humidification action ensures that even at high flow rates, the gas maintains sufficient humidity to prevent electrolyte membrane drying and deterioration while still achieving high productivity.
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 suppresses electrolyte membrane deterioration, enhances reactant availability, and reduces carbon corrosion by maintaining stable humidity and preventing water retention, leading to improved cell voltage stability and extended lifespan.
Implementation Method 1
a first porous separator having hydrophilic micropores and a second porous separator having hydrophilic micropores
Implementation Method 2
each having a cooling-water passage formed in a main surface of the fuel-electrode porous passage plate opposite to the main surface in which the fuel-electrode passage is arranged or in a main surface of the fuel-electrode porous passage plate opposite to the main surface in which the oxidant-electrode passage is arranged
Data Source
AI summary
According to the present embodiment, a fuel cell stack comprises a cell stack having a plurality of unit cells stacked therein, each of the unit cells including an electrolyte membrane, a fuel-electrode porous passage plate, and an oxidant-electrode porous passage plate, wherein in the cell stack, at least a part of one main surface of a conductive fuel-electrode porous passage plate is in contact with one main surface of a conductive oxidant-electrode porous passage plate, and a capillary force of water contained in a hydrophilic micropores of the conductive fuel-electrode porous passage plate and the conductive oxidant-electrode porous passage plate prevents an oxidant gas in an oxidant-electrode passage and a fuel gas in a fuel-electrode passage from directly mixing together.