Hydrogen Concentration Sensor with Isolated Detection Electrodes
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Solution Overview
Problem
Existing hydrogen concentration sensors for fuel cells face interference from potential shifts at the reference electrode when it evolves pure hydrogen, leading to inaccurate measurements due to the introduction of pure hydrogen, which affects the sensor's ability to accurately determine hydrogen concentration.
Innovation Solution
A hydrogen concentration sensor design featuring a hydrogen evolving electrode assembly and a detection electrode assembly, where the detection electrode assembly is exposed to evolved hydrogen without requiring any current supply, using isolating layers and a sealant to maintain electrical isolation and prevent interference, allowing for accurate hydrogen concentration measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference electrode evolves pure hydrogen by applying electrical current, then hydrogen concentration measurement is enabled, but potential shifts at the reference electrode occur causing measurement interference
Solution Approach 1:
The sensor is divided into functionally independent electrode assemblies: a hydrogen-evolving electrode assembly that generates hydrogen and a detection electrode assembly that measures hydrogen concentration. This segmentation allows the reference electrode to be isolated from current application, eliminating potential shifts while maintaining measurement capability through the detection assembly's exposure to evolved hydrogen.
Solution Approach 2:
Evolved hydrogen acts as an intermediary that transfers the function of measurement from the reference electrode to the detection electrode assembly. The hydrogen evolves at one electrode and diffuses to the detection electrode, allowing the detection electrode to measure concentration without requiring current application or serving as a reference electrode itself.
2Quantity of substance
If a reference electrode is used to evolve pure hydrogen, then hydrogen generation is achieved, but the reference electrode introduces interference with accurate measurement
Solution Approach 1:
The sensor separates hydrogen generation and measurement functions into distinct electrode assemblies. The hydrogen-evolving electrode assembly generates hydrogen without measurement interference, while the detection electrode assembly measures concentration without requiring current application or serving as a reference electrode.
Solution Approach 2:
The harmful function of the reference electrode (introducing potential shifts) is extracted and eliminated. Instead of using a reference electrode for both hydrogen evolution and measurement, the invention extracts the measurement function to a separate detection electrode assembly that does not evolve hydrogen itself.
3Measurement precision
If the detection electrode assembly is exposed to evolved hydrogen, then accurate concentration measurement is achieved, but electrical isolation must be maintained to prevent interference
Solution Approach 1:
The isolating layers act as intermediaries that allow hydrogen diffusion while blocking electrical current. These layers enable the detection electrode assembly to be exposed to evolved hydrogen for accurate measurement while maintaining electrical isolation from the hydrogen-evolving electrode assembly, preventing current interference.
Solution Approach 2:
The isolating layers are strategically positioned only where electrical isolation is needed, while allowing hydrogen diffusion. The sealant is applied locally at plate perimeters to create electrical isolation barriers without compromising the detection electrode's exposure to hydrogen for measurement.
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 improves sensor performance by eliminating the need for a reference electrode current, reducing potential shifts and enhancing measurement accuracy, resulting in more reliable hydrogen concentration detection.
Implementation Method 1
hydrogen evolving electrode assembly in a first location between two of the plates is configured to generate hydrogen
Implementation Method 2
Some such sensors rely on the Nernst Potential across two electrodes induced by a difference in hydrogen concentration at the respective electrodes
Data Source
AI summary
An illustrative example hydrogen concentration sensor includes a plurality of electrically conductive plates. A hydrogen evolving electrode assembly in a first location between two of the plates is configured to generate hydrogen. A detection electrode assembly in a second location between two of the plates is configured to provide an indication of a concentration of hydrogen in a fluid of interest. A plurality of isolating layers includes a first isolating layer at the first location between two of the plates and a second isolating layer at the second location between two of the plates. The first and second isolating layers each include a sealant that secures the two plates together and seals a perimeter around the electrode assembly at the corresponding location.