Bipolar Plate Inlet Layout for Uniform Flow in Alkaline Electrolyzers

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Solution Overview

Problem

Large-scale alkaline electrolyzers face issues with uneven internal flow fields, temperature differences, and increased resistance due to the increased number of electrolysis chambers, leading to inefficient hydrogen production and power consumption.

Innovation Solution

A bipolar plate design with strategically positioned alkaline solution inlet through-holes and gas-liquid mixing through-holes, along with end plates, ensures uniform alkaline solution distribution across electrolysis chambers, improving efficiency and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of electrolysis chambers is increased to achieve large-scale hydrogen production, then the production capacity is improved, but the uniformity of the flow field deteriorates and the temperature difference increases

Engineering Contradiction:
Improvehydrogen production capacityVSAvoidflow field uniformity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The single alkaline solution inlet is segmented into multiple inlet through-holes distributed across the bipolar plate structure. This segmentation allows the electrolyte to enter multiple electrolysis chambers simultaneously through different locations, preventing the flow from being concentrated in a single path and thereby maintaining flow field uniformity even as the number of chambers increases

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the bipolar plate are equipped with inlet through-holes at strategically positioned locations. This local quality approach ensures that each region of the electrolyzer has appropriate fluid entry points, creating locally optimized flow conditions that collectively maintain overall flow field uniformity across the entire large-scale device

Inventive Principle:
Principle #3Local quality

2Productivity

If the number of electrolysis chambers is increased to achieve large-scale hydrogen production, then the production capacity is improved, but the temperature difference among chambers increases

Engineering Contradiction:
Improvehydrogen production capacityVSAvoidtemperature uniformity
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The single temperature control point is segmented into multiple temperature control regions corresponding to different inlet through-hole locations. This allows for distributed thermal management where each region can be independently monitored and controlled, preventing hot spots and maintaining uniform temperature distribution across the expanded electrolyzer

Inventive Principle:
Principle #1Segmentation

3Productivity

If the number of electrolysis chambers is increased to achieve large-scale hydrogen production, then the production capacity is improved, but the resistance to electrolyte flow increases

Engineering Contradiction:
Improvehydrogen production capacityVSAvoidelectrolyte flow resistance
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The single flow path is segmented into multiple parallel flow paths, each originating from a different inlet through-hole. This segmentation reduces the flow resistance by distributing the electrolyte flow across multiple channels rather than forcing all flow through a single long path, thereby maintaining lower resistance even as the system scales up

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow distribution is transitioned from a one-dimensional sequential path to a two-dimensional distributed network of inlet through-holes across the bipolar plate. This dimensional change allows the electrolyte to access multiple chambers simultaneously through different spatial locations, reducing flow path length and resistance

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Device complexity

If a single alkaline solution inlet is used to simplify the structure, then the device complexity is reduced, but the mass transfer uniformity deteriorates

Engineering Contradiction:
Improveinlet structure complexityVSAvoidmass transfer uniformity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The single inlet structure is segmented into multiple inlet through-holes that are integrated into the bipolar plate. This segmentation maintains relatively simple device structure while dramatically improving mass transfer uniformity by distributing the alkaline solution to multiple chambers simultaneously through the segmented inlet points

Inventive Principle:
Principle #1Segmentation

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 achieves uniform alkaline solution distribution, enhancing hydrogen production efficiency and preventing operating state deterioration in large-scale alkaline electrolyzers.

Implementation Method 1

a first alkaline solution inlet through-hole group and a second alkaline solution inlet through-hole group, both of which are arranged at the lower part of the electrode frame and pass through the lower part of the electrode frame along the thickness direction of the electrode frame

Methodology Applied
Scientific EffectFluid flow distribution:

Implementation Method 2

a first gas-liquid mixing through-hole and a second gas-liquid mixing through-hole, both of which are arranged at the upper part of the electrode frame and pass through the upper part of the electrode frame along the thickness direction of the electrode frame

Methodology Applied
Scientific EffectGas-liquid mixing:

Implementation Method 3

the second through-holes of the first alkaline solution inlet through-hole group and the anode surface, the second through-holes of the second alkaline solution inlet through-hole group and the cathode surface, the first gas-liquid mixing through-hole and the anode surface, and the second gas-liquid mixing through-hole and the cathode surface are all communicated through a communication groove

Methodology Applied
Scientific EffectFluid communication:

Data Source

PatentEP4729659A1Bipolar plate, end plate and alkaline electrolyzer
Publication Date: 2026.04.22 HYDOTECH HYDROGEN ENERGY TECHNOLOGY CO LTD
  • EP4729659A1 patent drawingFigure 1~2
  • EP4729659A1 patent drawingFigure 3~4
  • EP4729659A1 patent drawingFigure 5~6

AI summary

The present application provides a bipolar plate, an end plate and an alkaline electrolyzer. The positions of a first alkali liquor inlet through hole group and a second alkali liquor inlet through hole group are rationally arranged at the bottom of an electrode frame, such that when the bipolar plate is applied to the alkaline electrolyzer, alkali liquor firstly enters a first alkali liquor inlet channel formed by first through holes of the first alkali liquor inlet through hole group and a second alkali liquor inlet channel formed by first through holes of the second alkali liquor inlet through hole group from one end of the alkaline electrolyzer. After arriving at the other end of the alkaline electrolyzer, the alkali liquor enters individual electrolysis cells from second through holes of the first alkali liquor inlet through hole group and second through holes of the second alkali liquor inlet through hole group, so as to realize uniform distribution of the alkali liquor, and solves the problem of the uneven distribution of the alkali liquor caused by the excess length of an electrolyzer body of a large alkaline electrolyzer, thus preventing the operating conditions of the alkaline electrolyzer from getting worse, improving the efficiency of hydrogen production, and finally achieving the purpose of saving the electric energy consumption of the alkaline electrolyzer.