Water Electrolysis Fuel Cell Reversible Cell Design
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Solution Overview
Problem
Existing water electrolysis/fuel cell power generation reversible cells face challenges in easily switching between modes due to conflicting hydrophilicity and water repellency requirements, leading to inefficient performance and slow mode switching.
Innovation Solution
A cell configuration with separate gas separators and water flow paths, along with water-repellent electrode layers, allows for perpendicular supply and discharge of water, oxygen, and hydrogen gases, enabling efficient switching between water electrolysis and fuel cell power generation modes without the need for drying or supplying water, facilitating immediate operational readiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water is supplied to the electrolyte layer during water electrolysis mode, then water electrolysis performance is improved, but water clogs the gas diffusion layer during fuel cell mode
Solution Approach 1:
The cell is divided into functionally independent flow paths: a water flow path for supplying water to the electrolyte layer during electrolysis mode, and separate gas flow paths for supplying hydrogen and oxygen during fuel cell mode. This segmentation prevents water from interfering with gas diffusion during fuel cell operation, resolving the contradiction between electrolysis performance and fuel cell reliability.
Solution Approach 2:
The patent inverts the traditional approach by making the gas diffusion layer water-repellent rather than water-attracting. This allows the same layer to serve dual purposes: enabling efficient gas diffusion during fuel cell mode while preventing water clogging, thereby maintaining fuel cell operation stability even when water is supplied during electrolysis mode.
2Reliability
If the gas diffusion layer is made hydrophobic to prevent water clogging, then fuel cell mode reliability is improved, but water supply to electrolyte during electrolysis mode becomes difficult
Solution Approach 1:
The flow path system is segmented into distinct channels: water is supplied through dedicated water flow paths that bypass the gas diffusion layer, while gas flow paths remain separate for hydrogen and oxygen supply. This segmentation allows the gas diffusion layer to be hydrophobic for reliable fuel cell operation while water supply efficiency is maintained through the separate water flow paths.
Solution Approach 2:
The patent introduces an intermediary water-repellent coating on the gas diffusion layer that acts as a selective barrier: it prevents water from penetrating and clogging the layer during electrolysis mode, while still allowing efficient gas diffusion during fuel cell mode. This intermediary layer resolves the contradiction between fuel cell reliability and water supply efficiency.
3Ease of manufacture
If the cell structure is simplified to reduce manufacturing complexity, then manufacturing cost is reduced, but mode switching performance deteriorates
Solution Approach 1:
The cell employs a segmented flow path design with separate water and gas flow channels, which can be integrated into the cell structure during manufacturing. This segmentation enables rapid mode switching between electrolysis and fuel cell operations without requiring complex external reconfiguration, thus maintaining both ease of manufacture and fast mode switching performance.
Solution Approach 2:
The cell structure is designed with multi-functional components that serve different purposes in different modes: the same electrodes function as both electrolysis electrodes and fuel cell electrodes, and the segmented flow paths automatically route water or gas based on operating mode. This universality allows simplified manufacturing while enabling rapid mode switching without performance deterioration.
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
The solution enables seamless switching between water electrolysis and fuel cell power generation modes, preventing water clogging and allowing stable operation in both modes immediately after switching, while maintaining compact cell stacking and improved efficiency.
Implementation Method 1
a water-repellent electrode (anode and cathode) having a two-layer structure including a gas diffusion electrode layer made up of a mixture of a semi-water repellent material and a catalyst
Implementation Method 2
a proton conductive porous electrolyte
Implementation Method 3
the water electrolysis cell includes a proton conductive porous electrolyte, an electrode (hereinafter also referred to as a 'water-repellent electrode') configured to include a water repellent material and bonded to each of both surfaces of the aforementioned porous electrolyte, and means for supplying water to the porous electrolyte, and is able to generate oxygen gas and hydrogen gas in the gas phase
Data Source
AI summary
A cell for water electrolysis/fuel cell power generation which includes a flow path configured to supply or discharge water in a first direction substantially perpendicular to a stacking direction of the cell; an oxygen-containing gas flow path configured to discharge or supply an oxygen-containing gas in a second direction substantially perpendicular to the stacking direction of the cell; and a hydrogen-containing gas flow path configured to discharge or supply the hydrogen-containing gas in a third direction substantially perpendicular to the stacking direction of the cell. Each of the oxygen-side electrode layer and the hydrogen-side electrode layer is an electrode layer having water repellency.