Fuel cell contamination detection

Abstract

The present disclosure provides fuel cell contamination detection. An automotive fuel cell system with an integrated optical contamination detection mechanism is presented. The automobile fuel cell system comprises a fuel cell which is connected to a hydrogen input pipe through an optical coupler. A laser is configured to generate a light beam that is focused by a lens through the optical coupler and into the hydrogen input tube. Contaminants flowing through the hydrogen input tube emit light back through an optical coupler and a lens, enabling detection and monitoring of these contaminants.

Description

Technical Field

[0001] This disclosure relates to pollution detection in fuel cells. Background Technology

[0002] Proton exchange membrane fuel cell stack cells can be prone to degradation when the supply fluid flow is contaminated with metal oxide particles, particularly iron or chromium oxides. These contaminants typically originate from corrosion of stainless steel components within the fuel cell system. Introducing these particles, even those at the nanoscale, can alter fuel cell performance. Conventional methods for detecting trace particulate contamination involve inserting filters and disassembling the system for sample collection. Summary of the Invention

[0003] An automotive fuel cell system includes: a fuel cell; a gas input pipe having an optical coupler and in fluid communication with the fuel cell; a laser configured to generate a light beam; and a lens configured to focus the light beam through the optical coupler and into the gas input pipe, such that contaminants flowing through the gas input pipe emit light back through the optical coupler and the lens. In some configurations, the automotive fuel cell system includes a spectrometer configured to detect the light emitted back through the optical coupler and the lens. The automotive fuel cell system may also include an optical filter configured to detect the light emitted back through the optical coupler and the lens. The spectrometer may include a detector, such as a photodiode, a charge-coupled device, or a complementary metal-oxide-semiconductor array. The spectrometer can detect particles in the nanometer to micrometer range. The light beam can heat contaminants to incandescence. The optical coupler may include fittings and an optically transparent insert. The optically transparent insert may be sapphire or quartz. A particulate contaminant sensor may be configured to provide diagnostic information during vehicle operation.

[0004] Another automotive fuel cell system includes: a fuel cell; a gas inlet pipe in fluid communication with the fuel cell; a laser configured to generate a light beam entering the gas inlet pipe; a spectrometer configured to receive the emitted light; and an optical coupler configured to direct light emitted due to the interaction of the light beam with contaminants flowing through the gas inlet pipe to the spectrometer. The automotive fuel cell system may include a lens configured to focus the light beam into the hydrogen inlet pipe. In some configurations, the automotive fuel cell system may include an optical filter configured to direct the light beam emitted through the optical coupler and the lens onto the spectrometer. The laser may be a solid-state laser. The light beam may excite contaminants to emit photons, or the light beam may heat the contaminants to incandescence. The optical coupler may include fittings and an optically transparent insert. The optically transparent insert may be sapphire or quartz. The fuel cell may allow real-time monitoring of contaminants in the gas inlet pipe.

[0005] Another automotive fuel cell system includes: a fuel cell; an interface tube in fluid communication with the fuel cell; a laser configured to generate a light beam; a first optical port coupled to the interface tube and configured to direct the light beam from the laser to the interface tube; a second optical port coupled to the interface tube and positioned non-coaxially relative to the light beam; and a detector coupled to the second optical port and configured to detect light scattered by contaminants in a gas flowing through the interface tube. The laser may be a solid-state laser. Attached Figure Description

[0006] Figure 1 This is a graph of the emission spectrum of iron obtained from laser-induced breakdown spectroscopy analysis;

[0007] Figure 2 This is a graph of the emission spectrum of chromium obtained from laser-induced breakdown spectroscopy analysis;

[0008] Figure 3 This is a schematic diagram of a car fuel cell system;

[0009] Figure 4 This is a schematic diagram of a single-ended contamination sensing configuration; and

[0010] Figure 5 This is a schematic diagram of a dual-end contamination sensing configuration. Detailed Implementation

[0011] This document describes embodiments. However, it should be understood that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The drawings are not necessarily drawn to scale. Some features may be enlarged or minimized to show details of specific components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art.

[0012] The various features shown and described with reference to any of the accompanying drawings may be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, for a particular application or implementation, various combinations and modifications of features consistent with the teachings of this disclosure may be desired.

[0013] This disclosure discloses a non-invasive optical sensor designed to detect and analyze contaminant particles in a fuel cell gas stream. The sensor can utilize various light-matter interaction techniques, such as elastic light scattering, laser-induced incandescence, or laser-induced breakdown spectroscopy. The presented sensor configuration allows for fine-tuning to accommodate each technique, with a single-end configuration suitable for both laser-induced incandescence and laser-induced breakdown spectroscopy, while elastic light scattering requires a non-zero arrangement between the light source and the detector.

[0014] Elastic light scattering is the phenomenon where light is scattered by particles or waves in a medium without any change in its wavelength. Elastic light scattering can be achieved using solid-state lasers. This process can be explained by different scattering theories, depending on the size of the scattering particles relative to the wavelength of the incident light. When the particles are much smaller than the wavelength of light, Rayleigh scattering occurs, resulting in a scattering intensity inversely proportional to the fourth power of the wavelength. This explains why shorter wavelengths (blue light) are scattered more than longer wavelengths (red light), making the sky appear blue. When the particle size is comparable to the wavelength of light, Mie scattering becomes significant. This type of scattering is less wavelength-dependent and can explain the white appearance of clouds containing water droplets of various sizes.

[0015] In laser-induced incandescence, a laser beam heats particles to incandescence, causing them to emit thermal radiation. The intensity and attenuation of this radiation are then analyzed using a spectrometer employing thermal emission spectroscopy to infer particle properties. The process can begin with rapid laser heating of the particles, typically to temperatures above 4000 K, causing them to emit a broad spectrum of light due to incandescence. As the particles cool, the emission intensity decreases, and this time-dependent decay is measured. By analyzing the decay curves, information about particle size and concentration can be obtained.

[0016] Laser-induced breakdown spectroscopy typically involves focusing a laser beam onto a sample, which causes the material to ionize, forming a plasma. The high temperature in the plasma excites and ionizes atoms, which then emit light as they return to lower energy states. The resulting emission spectrum contains peaks corresponding to the various elements present in the sample, allowing for qualitative and quantitative analysis using optical emission spectroscopy via spectrometers or optical filters.

[0017] The sensor utilizes a laser diode as its light source, capable of delivering high-power coherent light from the ultraviolet, visible, or near-infrared spectrum to the measurement volume. Neodymium-doped yttrium aluminum garnet laser diodes can be used as the light source for laser-induced breakdown spectroscopy and laser-induced incandescence. Signal detection can be achieved using photodiodes with interference filters to facilitate the capture of light at specific wavelengths. These wavelengths can vary depending on the technology employed. One configuration can be based on matching the laser diode to perform elastic light scattering to change the wavelength. In another configuration, the wavelength can be varied based on two colors redshifted from laser-induced incandescence. In yet another configuration, the wavelength can be altered to a specific color associated with a particular ionic substance in the laser-induced breakdown spectrum.

[0018] External hardware supplies current to the laser diode and processes the analog signal from the detector. The sensor is integrated with the fuel cell system via an optical port configured to withstand high temperatures and pressures. This can be achieved using stainless steel fittings that are welded or threaded into the fuel cell system hardware. The optical path is provided by sapphire or quartz inserts bonded to metal fittings or sealed with gaskets or O-rings.

[0019] This optical sensing method enables the non-invasive detection of nano- or micron-sized particles within the airflow of a fuel cell system. The sensors' capabilities range from simple qualitative indications of particle presence to more advanced quantitative measurements (such as particle diameter or elemental composition), depending on the sensor's complexity. The sensors' temporal resolution is sufficient to correlate particle detection with operating conditions, potentially enabling early detection of component degradation. Beyond simple detection, the sensors can also measure particle presence, atomic composition, and particle size in real time.

[0020] exist Figure 1 and Figure 2 The figure shows a graph of the emission spectrum from laser-induced breakdown spectroscopy analysis. Figure 1 The emission spectrum of iron is shown. The horizontal axis represents wavelength in nanometers, while the vertical axis shows line intensity in arbitrary energy flux units. The graph shows multiple peaks throughout the spectrum, with the most prominent peak appearing between 250 nm and 300 nm. Figure 2The emission spectrum of chromium is shown, where the horizontal axis represents wavelength in nanometers, and the vertical axis represents line intensity in arbitrary energy flux units. The chromium spectrum shows different peaks, with the most intense peaks appearing near 285 nm and 425 nm.

[0021] Figure 1 and Figure 2 The spectra shown demonstrate how different elements (iron and chromium in this example) possess unique spectral characteristics. This allows the sensor to identify specific contaminants in the fuel cell gas flow. For example, different peaks at 259.9 nm and 283.5 nm can be used to identify iron and chromium, respectively. The ability to distinguish different elements and their ionization states allows the sensor to provide information about the composition of contaminant particles. This enables detection systems incorporating sensors to detect and analyze nano- or micron-sized particles in fuel cell systems, potentially identifying contamination sources (e.g., component degradation) based on the elemental composition of the detected particles.

[0022] Figure 3 This is a schematic diagram of a vehicle fuel cell system 10 with a fuel cell 12. The fuel cell 12 has an interface pipe 14 in fluid communication with it. The interface pipe 14 fluidly couples the fuel cell 12 to a fuel cell system component 16. The fuel cell system component 16 may be a fuel tank or an exhaust outlet, depending on the configuration of the vehicle fuel cell system 10. Along the interface pipe 14 is a detection mechanism 18, which is configured to detect the flow of contaminants through the interface pipe 14. The detection mechanism 18 may use elastic light scattering, laser-induced incandescence, or laser-induced breakdown spectroscopy for contaminant detection. The detection mechanism 18 is coupled to a processor 22 via a communication line 20. The processor 22 is configured to analyze readings from the detection mechanism 18. The processor 22 can convert the spectral data or light scattering pattern from the detection mechanism 18 into meaningful information about the presence, size, or composition of contaminant particles. By performing real-time analysis, the processor 22 can provide timely information about the status of the vehicle fuel cell system 10. The processor 22 can also correlate data from the detection mechanism 18 with operating conditions.

[0023] Figure 4 and Figure 5 This is a schematic diagram of a pollutant sensing configuration. Figure 4The image shows a single-ended contamination sensing configuration 24 for an automotive fuel cell system. A hydrogen inlet pipe 26 is in fluid communication with the fuel cell, where the flow and detection of contaminant particles 28 occur. A laser 30 generates a beam 32 that passes through an optical coating component 34, which may be a beam splitter or a dichroic mirror. The optical coating component 34 allows the beam 32 to pass through while redirecting any reflected light. A lens 36 focuses the beam 32, which then passes through an optical adapter 38 that acts as an optical coupler. The optical adapter 38 docks with the hydrogen inlet pipe 26, thereby focusing the beam 32 into the hydrogen inlet pipe 26. The beam 32 is focused into a probe volume with a diameter of approximately 10 to 30 micrometers. Inside the hydrogen inlet pipe 26, the beam 32 interacts with the contaminant particles 28, thereby generating a light signal 40 indicating a laser-induced breakdown spectrum or laser-induced incandescence. The light signal 40 is reflected back through the optical adapter 38 and the lens 36. Then, the optical coating component 34 directs the reflected light to the detector 42 for analysis of contaminant particles 28, which may be a spectrometer.

[0024] Figure 5 This is a schematic diagram of a dual-end contamination sensing configuration 44 for an automotive fuel cell system, wherein an interface tube 46 is in fluid communication with the fuel cell. The interface tube 46 can be an inlet tube for fuel in the fuel cell or an exhaust outlet from the fuel cell. A laser 48 is configured to generate a beam 50. This beam 50 passes through a lens 52, which is configured to focus the beam 50 through a first optical port 54 coupled to and guiding the beam 50 into the interface tube 46. Inside the interface tube 46, the beam 50 interacts with contaminant particles 56, resulting in an elastic scattering effect that produces a scattered beam 58. The scattering process used can be Rayleigh or Mie scattering. A second optical port 60 is coupled to the interface tube 46 and positioned at an angle greater than 0 degrees but less than 180 degrees relative to the beam 50 from the laser 48. This angular positioning allows for the detection of the scattered beam 58. A detector 62 is connected to the second optical port 60. The detector 62 is configured to detect the scattered beam 58 by means of contaminant particles 56 in the gas flowing through the interface tube 46.

[0025] While exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms covered by the claims. Furthermore, the language used in this specification is descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of this disclosure.

[0026] As previously described, features of various embodiments can be combined to form other embodiments of the invention that may not be explicitly described or shown. While various embodiments may have been described as offering advantages or preferences over other embodiments or prior art implementations in terms of one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. Therefore, embodiments described as less desirable than other embodiments or prior art implementations in terms of one or more characteristics are not outside the scope of this disclosure and may be desirable for a particular application.

[0027] According to the present invention, an automotive fuel cell system is provided, comprising: a fuel cell; a gas input pipe including an optical coupler and in fluid communication with the fuel cell; a laser configured to generate a light beam; and a lens configured to focus the light beam through the optical coupler and into the hydrogen input pipe, such that contaminants flowing through the hydrogen input pipe emit light back through the optical coupler and the lens.

[0028] According to one embodiment, the invention is further characterized by a spectrometer configured to detect light emitted back through the optical coupler and the lens.

[0029] According to one embodiment, the invention is further characterized by an optical filter configured to guide light emitted back through the optical coupler and the lens onto the spectrometer.

[0030] According to one embodiment, the spectrometer is coupled to a photodiode detector.

[0031] According to one embodiment, the contaminant is in the nanometer to micrometer range.

[0032] According to one embodiment, the laser is also configured to generate a beam such that the beam heats the contaminant to incandescence.

[0033] According to one embodiment, the optical coupler includes an accessory and an optically transparent insert.

[0034] According to one embodiment, the optically transparent insert is sapphire or quartz.

[0035] According to the present invention, an automotive fuel cell system is provided, comprising: a fuel cell; a hydrogen input pipe in fluid communication with the fuel cell; a laser configured to generate a light beam; a spectrometer; and an optical coupler configured to guide light emitted due to the interaction of the light beam with contaminants flowing through the hydrogen input pipe to the spectrometer.

[0036] According to one embodiment, the invention is further characterized by a lens configured to focus a light beam into a hydrogen input tube.

[0037] According to one embodiment, the invention is further characterized by an optical filter configured to guide light emitted through the optical coupler and the lens onto the spectrometer.

[0038] According to one embodiment, the laser is a neodymium-doped yttrium aluminum garnet laser.

[0039] According to one embodiment, the laser is further configured to generate a beam such that the beam excites the contaminant to emit photons.

[0040] According to one embodiment, the laser is also configured to generate a beam such that the beam heats the contaminant to incandescence.

[0041] According to one embodiment, the optical coupler includes an accessory and an optically transparent insert.

[0042] According to one embodiment, the optically transparent insert is sapphire or quartz.

[0043] According to the present invention, an automotive fuel cell system is provided, comprising: a fuel cell; an interface tube in fluid communication with the fuel cell; a laser configured to generate a light beam; a first optical port coupled to the interface tube and configured to guide the light beam to the interface tube; a second optical port coupled to the interface tube and positioned non-coaxially relative to the light beam; and a detector coupled to the second optical port and configured to detect the light beam generated by the laser.

[0044] Light scattered by contaminants in the gas flowing through the interface tube.

[0045] According to one embodiment, the laser is a free-electron laser.

Claims

1. An automotive fuel cell system, comprising: a fuel cell; a hydrogen input tube comprising an optical coupler, in fluid communication with the fuel cell; a laser configured to generate a light beam; and a lens configured to focus the light beam through the optical coupler and into the hydrogen input tube such that a contaminant flowing through the hydrogen input tube emits light back through the optical coupler and the lens.

2. The automotive fuel cell system of claim 1, further comprising a spectrometer configured to detect the light emitted back through the optical coupler and the lens.

3. The automotive fuel cell system of claim 2, further comprising an optical filter configured to direct the light emitted back through the optical coupler and the lens onto the spectrometer.

4. The automotive fuel cell system of claim 1, wherein the laser is further configured to generate the light beam such that the light beam heats the contaminant to incandescence.

5. The automotive fuel cell system of claim 1, wherein the optical coupler comprises a fitting and an optically transparent insert.

6. The automotive fuel cell system of claim 5, wherein the optically transparent insert is sapphire or quartz.

7. An automotive fuel cell system, comprising: a fuel cell; a hydrogen input tube in fluid communication with the fuel cell; a laser configured to generate a light beam; a spectrometer; and an optical coupler configured to direct light emitted as a result of an interaction of the light beam with a contaminant flowing through the hydrogen input tube to the spectrometer.

8. The automotive fuel cell system of claim 7, further comprising a lens configured to focus the light beam into the hydrogen input tube.

9. The automotive fuel cell system of claim 8, further comprising an optical filter configured to direct light emitted through the optical coupler and the lens onto the spectrometer.

10. The automotive fuel cell system of claim 7, wherein the laser is a neodymium-doped yttrium aluminum garnet laser.

11. The automotive fuel cell system of claim 7, wherein the laser is further configured to generate the light beam such that the light beam excites the contaminant to emit photons.

12. The automotive fuel cell system of claim 7, wherein the laser is further configured to generate the light beam such that the light beam heats the contaminant to incandescence.

13. The automotive fuel cell system of claim 7, wherein the optical coupler comprises a fitting and an optically transparent insert.

14. An automotive fuel cell system, comprising: a fuel cell; an interface tube in fluid communication with the fuel cell; a laser configured to generate a light beam; a first optical port coupled to the interface tube and configured to direct the light beam into the interface tube; and a second optical port coupled to the interface tube and configured to direct light emitted from the interface tube. ​ a second optical port coupled to the interface tube and positioned non-coaxially relative to the optical beam; and a detector coupled to the second optical port and configured to detect light scattered by contaminants in the gas flowing through the interface tube.

15. The automotive fuel cell system of claim 14, wherein the laser is a free electron laser.

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