Nickel-Coated BOS Components in Alkaline Electrolysis
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Solution Overview
Problem
In alkaline electrolysis, the accumulation of metal cations such as iron, chromium, manganese, and molybdenum in the electrolyte leads to accelerated aging of electrodes, increased electrical energy consumption, and potential dendrite formation causing short circuits.
Innovation Solution
The electrolysis arrangement features a nickel layer with a thickness of at least 0.1 mm and a nickel content of at least 98 wt.% on the inner side regions of components in contact with the alkaline electrolysis medium, reducing the risk of cation accumulation and electrode degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel-based materials are used for BOS components, then structural strength and pressure containment are improved, but metal cation accumulation in the electrolyte increases leading to electrode aging
Solution Approach 1:
A nickel layer is introduced as an intermediary barrier between the steel-based BOS components and the alkaline electrolysis medium. This nickel layer prevents direct contact between the electrolyte and steel materials, thereby blocking metal cation accumulation while allowing the steel structure to maintain its structural strength and pressure containment functions.
Solution Approach 2:
The solution employs a composite structure combining steel-based materials (for structural strength) with a nickel coating layer (for chemical compatibility). This composite approach allows the system to simultaneously achieve mechanical strength from the steel substrate and corrosion resistance from the nickel layer, preventing cation accumulation without compromising structural integrity.
2Productivity
If elevated temperatures are operated to increase conductivity and reaction rate, then electrolysis efficiency is improved, but metal cation leaching from steel components increases
Solution Approach 1:
The nickel layer serves as a temperature-stable intermediary that remains effective at elevated operating temperatures. It prevents metal cation leaching from steel components even under high-temperature conditions, thereby allowing the system to operate at elevated temperatures for improved efficiency without increasing harmful cation accumulation in the electrolyte.
3Ease of manufacture
If thinner nickel layers are used to reduce cost, then manufacturing cost decreases, but cation accumulation and electrode aging still occur
Solution Approach 1:
The patent specifies a minimum nickel layer thickness of 0.1 mm as a critical parameter threshold. Below this thickness, the nickel layer becomes insufficient to prevent effective cation accumulation. By ensuring the nickel layer meets or exceeds this thickness parameter, the system achieves both cost-effectiveness and reliable protection against electrode aging.
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 use of a high-nickel content layer effectively prevents or limits the accumulation of metal cations, thereby extending the service life of electrodes, reducing energy consumption, and minimizing the risk of short circuits.
Implementation Method 1
the inner side region is at least partially formed from a nickel layer, and wherein the nickel layer has a layer thickness of at least 0.1 mm and a nickel content of at least 98 wt. %
Implementation Method 2
hydroxide ions must diffuse from one half-cell to the other through a separating element that separates the cathode and anode sides of the electrolysis cell
Implementation Method 3
the electrolysis medium circulates in the electrolysis stack and in the BOS components of the electrolysis system, typically at a temperature of 60°C to 90°C
Data Source
Figure 1
AI summary
The invention relates to an electrolysis arrangement for operation with an alkaline electrolysis medium, comprising a first and a second region. The first region comprises an electrolysis stack with a plurality of electrolysis cells and is configured to generate a product gas in an anode region and to generate a product gas in a cathode region from the alkaline electrolysis medium. The second region is in fluid communication with the first region and has a plurality of components configured to discharge electrolysis medium enriched in product gas from the first region, to introduce electrolysis medium depleted in product gas into the first region, and to separate the generated product gases from the electrolysis medium.The components of the second region have an inner side region which is designed for direct contact with the alkaline electrolysis medium, wherein the inner side region is formed at least partially from a nickel layer, and wherein the nickel layer has a layer thickness of at least 0.1 mm and a nickel content of at least 98 wt.%.