Capacitive Hydrogen Sensor with Palladium Membrane
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Solution Overview
Problem
Existing hydrogen sensors in automotive technology face challenges with insufficient response time, limited measuring range, cross-sensitivity to other components, and high construction costs, particularly in detecting hydrogen concentrations in fuel cell vehicles.
Innovation Solution
A sensor element with a thin, movable palladium-based measuring membrane that stores hydrogen to form palladium hydride, causing compressive strain and allowing for capacitive measurement of hydrogen concentration, utilizing a silicon substrate and insulation layer to minimize distance and maximize sensitivity, and optionally incorporating a second sensor for temperature calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed electrode and membrane structure with movable electrode is used, then the sensor can detect gas absorption, but the response time is insufficient
Solution Approach 1:
The patent applies the dynamics principle by making the measuring membrane itself conductive and movable, replacing the traditional fixed electrode-membrane-movable electrode structure. The conductive membrane can dynamically respond to gas absorption by changing its position and capacitance, significantly improving response time while maintaining detection precision.
Solution Approach 2:
The patent extracts the electrode function from the separate membrane structure and integrates it directly into the measuring membrane by making the membrane itself conductive. This eliminates the need for separate fixed and movable electrodes, simplifying the structure and accelerating the response time.
2Productivity
If conventional sensor structures are used, then the sensor can operate, but the measuring range is limited above the minimum required range
Solution Approach 1:
The patent applies parameter changes by adjusting the membrane thickness, conductivity, and material composition to optimize the measuring range. By changing these parameters, the sensor achieves the minimum required measuring range without excessive range, improving productivity while maintaining adaptability to specific automotive hydrogen detection requirements.
3Measurement precision
If conventional sensor designs are used, then the sensor can detect hydrogen, but cross-sensitivity to other components such as helium or volatile organic compounds occurs
Solution Approach 1:
The patent applies local quality by selecting specific conductive materials for the measuring membrane that have selective affinity for hydrogen. The membrane's local material properties are optimized to preferentially absorb hydrogen over other gases like helium or volatile organic compounds, reducing cross-sensitivity while maintaining hydrogen detection precision.
4Reliability
If expensive assembly and connection technology is used, then the sensor can be manufactured, but the construction costs are high
Solution Approach 1:
The patent applies merging by combining the membrane and electrode functions into a single conductive measuring membrane structure. This integration eliminates the need for complex assembly and connection technology between separate components, significantly reducing construction costs while maintaining sensor reliability through the unified structure.
Solution Approach 2:
The patent uses a thin conductive membrane that serves both structural and sensing functions. This thin-film approach simplifies manufacturing compared to bulky assembled structures, reducing costs while maintaining reliability through the membrane's inherent flexibility and responsiveness.
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 provides enhanced sensitivity, response time, and selectivity for hydrogen detection, addressing the limitations of existing sensors while maintaining mechanical stability and reducing costs through a monolithic structure and efficient manufacturing process.
Implementation Method 1
The sensor element comprises a measuring membrane (24) arranged partially on the insulation layer (20) and at least partially movable relative to the substrate (18). The cover layer (34) is at least partially made of palladium. Hydrogen is incorporated into palladium with a particularly high selectivity, forming palladium hydride (H-Pd) in the palladium.
Implementation Method 2
The properties of the fluid medium, and in particular the hydrogen content in the measuring gas 16, can be detected based on a capacitance between the substrate 18, which acts as one electrode, and the exposed structure in the form of the measuring membrane 24, which acts as another electrode.
Implementation Method 3
The sensor element (10) comprises a substrate (18). The substrate (18) is made at least partially of an electrically conductive material, such as silicon. An insulating layer (20) is arranged on the substrate (18).
Data Source
Figure 1~4
Figure 5
Figure 6A~6I
AI summary
A sensor element (10) is proposed for detecting at least one property of a fluid medium (12) in at least one measuring chamber (14), in particular for detecting an H2 content in a measuring gas (16).The sensor element (10) comprises a substrate (18) that is at least partially made of an electrically conductive material, an insulating layer (20) that is at least partially made of an electrically insulating material and that is arranged on the substrate (18), and a measuring membrane (24) that is partially on the insulating layer (20) and at least partially movably arranged relative to the substrate (18), wherein the measuring membrane (24) has a membrane layer (32) that is at least partially made of an electrically conductive material, and a cover layer (34) that is at least partially made of palladium and is arranged in a predetermined pattern on the membrane layer (32), wherein the property of the fluid medium (12) can be detected based on a capacitance between the substrate (18) and the measuring membrane (24).