Electrolysis Cell Separator Wettability for Gas-Water Separation

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Solution Overview

Problem

Existing water electrolysis systems face performance deterioration due to generated oxygen inhibiting water movement at the anode and water accompanying hydrogen ions inhibiting hydrogen movement at the cathode, hindering efficient gas and water separation.

Innovation Solution

The water electrolysis cell design incorporates an anode separator with water-repellent channels and a cathode separator with hydrophilic channels, ensuring efficient separation of generated gases and liquids by guiding water away from the anode and attracting it to the cathode, thereby preventing inhibition of gas movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If water is supplied to the anode gas diffusion layer for efficient electrolysis, then electrolysis performance is improved, but generated oxygen inhibits water movement and deteriorates performance

Engineering Contradiction:

Improveelectrolysis performanceVSAvoidoxygen inhibition of water movement

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The anode separator channel wall face is imparted with water repellency (hydrophobicity) specifically at the channel interface, while other parts of the system maintain normal properties. This local modification causes water to be repelled from the channel walls and directed toward the gas diffusion layer, preventing water accumulation that would inhibit oxygen removal while still enabling efficient water supply for electrolysis.

Inventive Principle:

Principle #3Local quality

2Reliability

If water accompanies hydrogen ions permeating through the electrolyte membrane to the cathode, then ion transport is enabled, but water inhibits hydrogen movement and deteriorates performance

Engineering Contradiction:

Improveion transport functionVSAvoidwater inhibition of hydrogen movement

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cathode separator channel wall face is imparted with hydrophilicity specifically at the channel interface, while maintaining normal properties elsewhere. This local hydrophilic modification attracts water to the channel walls, creating a hydrophilic barrier that prevents water from accumulating at the cathode gas diffusion layer interface, thereby preventing water from inhibiting hydrogen movement while still allowing ion transport.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional separators are used without surface treatment, then manufacturing is simple, but gas and water are not efficiently separated leading to performance deterioration

Engineering Contradiction:

Improveseparator manufacturing simplicityVSAvoidgas-water separation efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The surface properties of the separator channel wall faces are modified by imparting water repellency to the anode side and hydrophilicity to the cathode side. This changes the wettability parameter of the separator surfaces, enabling efficient gas-water separation through capillary pressure differences without requiring complex structural modifications, thus maintaining ease of manufacture while dramatically improving separation efficiency.

Inventive Principle:

Principle #35Parameter changes

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 enables smooth water electrolysis performance by effectively separating gases and liquids, suppressing performance deterioration and enhancing efficiency.

Implementation Method 1

a wall face of the first channel in the anode separator is imparted with water repellency

Methodology Applied

Scientific EffectWater repellency (Hydrophobicity): Hydrophobe

Implementation Method 2

a wall face of the second channel in the cathode separator is imparted with hydrophilicity

Methodology Applied

Scientific EffectHydrophilicity: Hydrophile

Data Source

PatentUS12577691B2Water electrolysis cell and water electrolysis stack

Publication Date: 2026.03.17 TOYOTA JIDOSHA KK

AI summary

A water electrolysis cell includes an anode disposed on one side across a solid polymer electrolyte membrane and a cathode disposed on the other side. The anode is configured of an anode catalyst layer, an anode gas diffusion layer, and an anode separator, laminated in that order from a side of the solid polymer electrolyte membrane. The cathode is configured of a cathode catalyst layer, a cathode gas diffusion layer, and a cathode separator, laminated in that order from the side of the solid polymer electrolyte membrane. A first channel is provided in the anode separator, and a wall face of the first channel in the anode separator is imparted with water repellency. A second channel is provided in the cathode separator, and a wall face of the second channel in the cathode separator is imparted with hydrophilicity.