Electrolysis Cell Reverse Current Absorbing Layer
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Solution Overview
Problem
The degradation of cathodes in electrolysis cells due to reverse current during shutdown is a significant issue, particularly with Raney nickel peeling off from current collectors and potential heat generation or firing, which complicates handling and increases costs, and existing solutions are not applicable to all electrode structures or require protection currents.
Innovation Solution
Incorporating a reverse current absorbing layer with a substrate and a layer formed on it, electrically connected to the cathode, using elements with lower oxidation-reduction potentials, such as Ni or NiO, to absorb and oxidize the reverse current, thereby preventing cathode degradation without the need for protection currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Raney nickel is used on the cathode surface to prevent reverse current degradation, then cathode protection is improved, but adhesion strength deteriorates causing peeling off
Solution Approach 1:
The invention uses a composite structure consisting of a current collector substrate and a Raney nickel layer formed thereon. The current collector provides mechanical strength and adhesion, while the Raney nickel layer provides reverse current absorption capability. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The Raney nickel layer is formed as a porous structure with controlled pore size and distribution. The porous structure increases the surface area for reverse current absorption while maintaining adequate adhesion to the current collector. The pore structure allows electrolyte penetration and enhances the electrochemical activity for reverse current mitigation.
2Reliability
If Raney nickel with large specific surface area is used to absorb reverse current, then reverse current absorption is improved, but heat generation and firing risk increase
Solution Approach 1:
The invention controls the specific surface area of the Raney nickel layer within an optimal range and adjusts the pore size distribution to balance reverse current absorption capacity with heat dissipation. By optimizing these parameters, the layer absorbs reverse current effectively while minimizing excessive heat generation and firing risks.
Solution Approach 2:
The Raney nickel layer exhibits non-uniform pore size distribution and density across different regions. Areas with higher reverse current density have optimized local properties for maximum absorption, while other regions are designed with properties that facilitate heat dissipation and prevent localized overheating.
3Productivity
If the electrolysis tank facility is increased in size with more electrolysis cells, then productivity is improved, but reverse current magnitude increases causing more degradation
Solution Approach 1:
The invention divides the cathode structure into functionally distinct segments: a current collector substrate for mechanical support and electrical conduction, and a Raney nickel layer for reverse current absorption. This segmentation allows each component to be optimized for its specific function, enabling the system to handle larger reverse currents in scaled-up facilities.
Solution Approach 2:
The Raney nickel layer acts as an intermediary between the current collector and the electrolyte, specifically designed to absorb reverse current before it reaches the main cathode structure. This intermediary layer protects the cathode from degradation while allowing the electrolysis tank to be scaled up for increased 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 solution effectively suppresses cathode degradation by absorbing reverse currents, preventing peeling and heat generation, and simplifies handling, while being compatible with various electrode structures without the need for protection currents, thus enhancing durability and operational safety.
Implementation Method 1
a reverse current absorbing layer with a substrate and a layer formed on it, electrically connected to the cathode, using elements with lower oxidation-reduction potentials, such as Ni or NiO, to absorb and oxidize the reverse current
Implementation Method 2
An ion exchange membrane method using an electrolysis tank equipped with an ion exchange membrane is mainly used in the electrolytic decomposition (hereinafter, referred to as the 'electrolysis') of an aqueous solution of alkali metal chloride such as brine
Data Source
AI summary
Provided is an electrolysis cell capable of suppressing the degradation of a cathode by the reverse current at the time of stopping electrolysis. According to an aspect of the invention, there is provided an electrolysis cell comprising an anode chamber, a cathode chamber, a partition wall separating the anode chamber from the cathode chamber, an anode installed in the anode chamber, a cathode installed in the cathode chamber, and a reverse current absorbing body having a substrate and a reverse current absorbing layer formed on the substrate and installed in the cathode chamber, in which the anode and the cathode are electrically connected and the cathode and the reverse current absorbing layer are electrically connected.