System for measuring at least one chemical component of a flowing fluid for an electrochemical-generator system

Abstract

The invention relates to a system (100) for measuring at least one chemical component of a flowing fluid for an electrochemical-generator system, the measuring system comprising: - a light source (111) generating a light beam, - a double-pass measurement cell (120) comprising an inlet opening (121) configured to let the fluid enter, an outlet opening configured to let the fluid exit, and two portholes placed on a path of the fluid, said portholes being positioned facing each other on a main optical axis transverse to the flow of the fluid and being configured to transmit the light beam, - a reflective optical device (130) positioned to reflect the light beam in the direction of the flowing fluid through the portholes, and - a Raman spectrometer (112) configured to receive the light beam, with a view to detecting a Raman signal emitted by the flowing fluid and to deducing therefrom a measurement of at least one chemical component of the flowing fluid.

Description

SYSTEM FOR MEASURING AT LEAST ONE CHEMICAL COMPONENT OF A FLOWING FLUID FOR ELECTROCHEMICAL GENERATOR SYSTEM TECHNICAL FIELD OF THE INVENTION

[0001] The present invention generally relates to the measurement of fluid concentration, in particular gas.

[0002] It relates more particularly to a system for measuring at least one chemical component of a flowing fluid for an electrochemical generator system of the fuel cell or electrolyser type.

[0003] The invention finds a particularly advantageous application in the measurement of gas entering and / or leaving such an electrochemical generator system. STATE OF THE ART

[0004] An electrochemical generator system such as a fuel cell generates electrical energy from the oxidation of fuel. This fuel is, for example, hydrogen. This produces electricity from hydrogen.

[0005] Conversely, an electrochemical generator system such as an electrolyzer can generate a chemical component from electrical energy. For example, an electrochemical generator system comprising an electrolytic cell based on the electrolysis of water can generate hydrogen and oxygen using electrical energy. This results in the generation of hydrogen.

[0006] In order to be able to characterize the state of such an electrochemical generator system in operation, and thus estimate the performance in real time, it may be interesting to measure the concentrations of the different chemical elements entering and / or leaving the electrochemical generator system.

[0007] Today, solutions consist of extracting part of the gas at the inlet or outlet of the electrochemical generator system and analyzing said gas with or without destruction of the extracted sample.

[0008] Gas extraction, especially when it is destroyed during analysis, causes disruptions in the operation of the electrochemical generator system. When the extracted gas is not destroyed but reinjected into the gas circuit, this causes, for example, a disruption in the measurement time.

[0009] In addition, gas extraction can cause pressure and temperature changes that destabilize the gas and can cause measurement errors.

[0010] Finally, today, many measuring systems use infrared which is not compatible with fluids containing a high level of water vapor.

[0011] In order to perform measurements in real time, it is also important to be able to obtain a high measurement frequency, and therefore a good signal-to-noise ratio allowing the integration time to be reduced. PRESENTATION OF THE INVENTION

[0012] In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes a system for measuring fluid entering or leaving an electrochemical generator system, the measuring system operating in real time and without extraction and isolation of said fluid from the circuit of the electrochemical generator system.

[0013] More particularly, the invention proposes a system for measuring at least one chemical component of a flowing fluid for an electrochemical generator system, the measuring system comprising: - a Raman spectrometry apparatus comprising a light source, a Raman spectrometer comprising a detection system and a processing system, the light source being configured to generate an excitation light beam, - a double-pass measuring cell comprising a fluid conduit having an inlet opening configured to allow the flowing fluid to enter and an outlet opening configured to allow the flowing fluid to exit, the measuring cell comprising a first sealed porthole and a second sealed porthole, the two portholes being arranged laterally on the fluid conduit downstream of the inlet opening and upstream of the outlet opening, the two portholes being positioned opposite each other on a main optical axis transverse to the fluid conduit and configured to receive the excitation light beam and transmit a first light beam formed by diffusion and / or simple transmission of the excitation light beam through the flowing fluid in the fluid conduit, and - an at least partially reflective optical device positioned to receive the first light beam transmitted by the two portholes and configured to reflect the first light beam towards the flowing fluid through the two portholes to form a second light beam formed by diffusion and / or double transmission of the excitation light beam through the flowing fluid and the two portholes, the Raman spectrometer being configured to receive the second light beam, the detection system being adapted to detect a Raman signal emitted by the flowing fluid and the processing system being adapted to deduce therefrom a measurement of at least one chemical component of the flowing fluid.

[0014] Thus, thanks to the invention, the Raman spectrometer makes it possible to analyze the fluid flow in the continuity of its flow when the fluid flow is in the double-pass cell, without deviation or extraction. The measuring system then does not disturb the fluid and makes it possible to carry out online measurements directly on the fluid flow line, without interruption of the flow, and without pressurization of the fluid.

[0015] In addition, the portholes facing each other in the double-pass cell as well as the arrangement of said portholes with the optical device on the main optical axis allows for minimal bulk of the measuring system.

[0016] Finally, the arrangement of the measuring system and the double-pass cell allows double excitation of the fluid and thus a better signal-to-noise ratio. This signal-to-noise allows for a real-time acquisition frequency of between 0.1 hertz (Hz) and 100 Hz, for example 1 Hz. The signal-to-noise also allows for very high-precision measurements, making it possible in particular to detect very small quantities of fluid, for example nitrogen from 100 ppm to 500 ppm, without recirculating the fluid and without pressurizing the fluid.

[0017] In one embodiment, the measuring cell is connected to a fluid conveyance conduit flowing into or out of an electrochemical generator system.

[0018] For example, the measuring cell is connected to an output of an electrochemical generator system of the electrolyser type, in particular for the generation of hydrogen, and the Raman spectrometry device is suitable for measuring the concentration of at least one chemical component among water, for example in the form of water vapour, nitrogen, hydrogen and oxygen.

[0019] Alternatively or additionally, the measuring cell is connected to an input or an output of an electrochemical generator system of the hydrogen fuel cell type for generating electricity from hydrogen and the Raman spectrometry apparatus is adapted to measure the concentration of at least one chemical component among water, nitrogen, hydrogen and oxygen.

[0020] Advantageously, the inlet opening or the outlet opening of the measuring cell is connected via a fluid flow conduit to the electrochemical generator system.

[0021] Advantageously, the cross-section of the inlet opening and the cross-section of the outlet opening of the measuring cell are each greater than or equal to the cross-section of the fluid flow conveyance conduit of the electrochemical generator system.

[0022] Advantageously, an optical system is arranged between the light source and the first porthole, the optical system being configured to focus the excitation light beam in the measuring cell between the two portholes.

[0023] According to a particular and advantageous aspect, the at least partially reflective optical device is configured to reflect and focus the first light beam in the measuring cell between the two portholes.

[0024] According to another particular and advantageous aspect, the measuring cell comprises at least one thermal unit configured to maintain the first porthole and / or the second porthole at a temperature greater than or equal to a threshold temperature.

[0025] Optionally, the first window comprises a first glass slide and the second window comprises a second glass slide, the first, respectively second, glass slide being manufactured from a glass among a borosilicate glass, an aluminosilicate glass or an alkali-aluminosilicate glass. Advantageously, the measuring system comprises a second measuring cell and the Raman spectrometry apparatus comprises another light source capable of emitting another excitation light beam, the detection system comprising a light sensor comprising pixels arranged in several lines and configured to simultaneously detect the Raman signal induced by the light source and a second Raman signal emitted by the flowing fluid when the flowing fluid is excited by the other excitation light beam.

[0026] The invention also relates to a system for measuring at least one fluid entering and / or leaving an electrochemical generator system, the measuring system operating in real time and without extraction and isolation of said fluids from the circuit of the electrochemical generator system.

[0027] More particularly, the invention proposes a system for measuring at least one chemical component of a flowing fluid for an electrochemical generator system comprising a plurality of inlet and / or outlet fluid conduits, the measuring system comprising - a Raman spectrometry apparatus comprising a light source, a Raman spectrometer comprising a detection system and a processing system, the light source being configured to generate an excitation light beam, a beam splitter arranged to receive the excitation light beam and form a plurality of divided excitation light beams, - a plurality of double-pass measuring cells each arranged on an inlet or outlet fluid conduit of the electrochemical generator system, each double-pass measuring cell comprising a fluid conduit having an inlet opening configured to allow the fluid to enter in flow coming from said inlet or outlet fluid conduit of the electrochemical generator system and an outlet opening configured to allow the fluid to exit in flow, each measuring cell comprising a first sealed porthole and a second sealed porthole, the two ports of each measuring cell being arranged laterally on the fluid conduit downstream of the inlet opening and upstream of the outlet opening,the two portholes of each measuring cell being positioned opposite each other on a main optical axis transverse to the fluid conduit and configured to receive a divided excitation light beam and transmit a first light beam formed by diffusion and / or simple transmission of the divided excitation light beam through the fluid flowing in the fluid conduit, and, - an at least partially reflective optical device positioned to receive the first light beam transmitted by the two portholes and configured to reflect the first light beam towards the flowing fluid through the two portholes to form a second light beam formed by diffusion and / or double transmission of the excitation light beam through the flowing fluid and the two portholes, the Raman spectrometer being configured to receive from each double-pass measuring cell the second light beam, the detection system being adapted to separately detect a Raman signal emitted by the flowing fluid from each double-pass measuring cell and the processing system being adapted to deduce therefrom a measurement of at least one chemical component of the flowing fluid in each double-pass measuring cell.

[0028] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0029] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0030] On the attached drawings:

[0031] Figure 1 is a schematic view of a measuring system according to one embodiment of the invention;

[0032] Figure 2 is a schematic view of part of the measurement system in application to a fuel cell type electrochemical generator system;

[0033] Figure 3 is a schematic view of part of the measuring system;

[0034] Figure 4 is a schematic view of part of the measuring system;

[0035] Figure 5 is a schematic view of a measuring cell according to the present disclosure;

[0036] Figure 6 is a schematic longitudinal sectional view of the measuring cell of Figure 4;

[0037] Figure 7 is a schematic view of a portion of the measuring cell of Figure 6;

[0038] Figure 8 is a graph representing an example of a spectrometer calibration function;

[0039] Figure 9 is a graph showing an example of a spectral measurement acquired by the measurement system; and

[0040] Figure 10 is a graph representing an example of the evolution of a Raman signal representative of dihydrogen as a function of time;

[0041] Figure 11 is a schematic view of a multi-measuring cell system used, for example, in a fuel cell type electrochemical generator system.

[0042] In Figure 1, there is shown a schematic view of a measuring system 100 making it possible in particular to measure concentrations of chemical components present in a flowing fluid 101. The fluid can be in gaseous or liquid form.

[0043] The measuring system 100 here comprises a Raman spectrometry device 110, a double-pass measuring cell 120, an optical device 130 and an optical system 140.

[0044] The measurement system is particularly suitable for measuring flowing fluids for an electrochemical generator system 200. The electrochemical generator system 200 can be used as an electrolyzer. For example, the electrochemical generator system 200 is an electrolyzer used for the production of hydrogen. The electrochemical generator system 200 then consumes electricity in order to produce hydrogen.

[0045] In another application, the electrochemical generator system 200 is used to generate electricity. In this case, the electrochemical generator system consumes a fuel, for example hydrogen, in order to produce electricity.

[0046] Advantageously, the Raman spectrometry apparatus is suitable for measuring the concentration of at least one chemical component among water, for example in the form of water vapor, nitrogen, hydrogen and oxygen.

[0047] The measuring system 100 is shown in use on an electrochemical generator system 200 of the fuel cell type in FIG. 2. In FIG. 2, the electrochemical generator system 200 is of the electricity generator type. At the inlet, air and dihydrogen are injected into the fuel cell. The combustion generates electricity. At the outlet, the fluid is conveyed by two conduits 201, one conduit 201 on the anode, the other conduit 201 on the cathode of the fuel cell. A double-pass measuring cell 120 is arranged on at least one conduit 201 to measure the fluid in flow 101 leaving the fuel cell 200. Advantageously, each conduit 201 is equipped with a double-pass measuring cell 120 to simultaneously detect the fluids on the conduit 201 connected to the anode and respectively on the conduit 201 connected to the cathode.

[0048] A portion of the measurement system 100 is shown in use in Figure 4.

[0049] The Raman spectrometry apparatus 110 comprises an interface box 115, a light source 111 and a Raman spectrometer 112.

[0050] The measuring principle is shown schematically in Figure 3.

[0051] The light source 111 is configured to generate an excitation light beam 116.

[0052] The interface box 115 is located as close as possible to the measuring cell 120. The interface box 115 makes it possible to make the measurement interface with the measuring cell.

[0053] Preferably, the light source 111 is external to the interface box 115 and the excitation light beam 116 is routed to the interface box via a fiber optic cable FO.E. The excitation light beam 116 is transmitted to the measuring cell 120 via the interface box 115.

[0054] Alternatively, the light source 111 is positioned in the interface housing 115 of the Raman spectrometry device 110.

[0055] Advantageously, as illustrated in Figure 4, the double-pass measuring cell 120, the optical device 130, the optical system 140 and the interface box 115 are integrated, for example on a plate forming an optomechanical support, to form a Raman probe 150 connected by optical fibers to the light source 111 and to the Raman spectrometer 112. In this way, a single light source 111 and a single Raman spectrometer 112 can be connected to several local Raman probes 150 arranged at the input and / or output of the electrochemical generator system 200.

[0056] The light source 111 is preferably a laser having a high intensity. Here, the light source 111 is for example a laser with a power of 1.5 W which emits a monochromatic light beam at a wavelength of 532 nm. The light source is of high power in order to obtain a Raman signal having an intensity sufficiently strong to allow an integration time compatible with real-time monitoring, for example at a rate of approximately 1 Hz.

[0057] Alternatively, the excitation light beam is generated from any light source suitable for generating parts of the spectrum or the entire spectrum.

[0058] The measuring cell 120 comprises a fluid conduit 129 having an inlet opening 121 and an outlet opening 122, a first sealed porthole 123 and a second sealed porthole 124.

[0059] The inlet opening 121 is connected to a first flowing fluid conduit 201 and configured to allow the flowing fluid 101 to enter.

[0060] The outlet opening 122 is connected to a second flowing fluid conduit 202 and configured to discharge the flowing fluid 101. The fluid conduit 129 guides the flowing fluid 101 entering through the inlet opening 121 to the outlet opening 122.

[0061] In order not to cause any change in pressure or flow rate of the flowing fluid 101, the cross-section of the inlet opening 121, the cross-section of the outlet opening 122 and the cross-section of the fluid conduit 129 are each greater than or equal to the cross-section of the flowing fluid conveying conduits 201, 202.

[0062] For example, here, the conveying conduits 201, 202 and the measuring cell 120 have a circular section, the internal diameter of the section of the measuring cell 120 as well as those of the two inlet 121 and outlet 122 openings is 16 mm and is identical to the internal diameter of the two conveying conduits 201, 202. The pressure of the fluid flowing in the measuring cell is then identical to the pressure of the fluid flowing in the conduits 201, 202. The total pressure of the fluid flowing in the conduits 201, 202 is for example 2 bars.

[0063] The two portholes 123, 124 are arranged laterally on the fluid conduit 129 downstream of the inlet opening 121 and upstream of the outlet opening 122. The two portholes 123, 124 are positioned opposite each other. For example, since the fluid conduit 129 is of circular section, two portholes 123, 124 are arranged diametrically opposite each other. In another example, since the fluid conduit 129 is of square or rectangular section, two portholes 123, 124 are arranged on two opposite faces of the fluid conduit 129. In this way, the flowing fluid 101 passes between the two portholes 123, 124.

[0064] The measuring cell 120 is positioned so that the two portholes 123, 124 are on a main optical axis OA transverse to the flow of the fluid.

[0065] The two portholes 123, 124 are configured to transmit the excitation light beam 116. For example, the excitation light beam propagates along a main illumination axis aligned with the main optical axis.

[0066] The two portholes 123, 124 are configured to transmit a first light beam 117 formed by diffusion and / or simple transmission of the excitation light beam through the flowing fluid 101.

[0067] In other words, the measuring cell 120 is integrated into the fluid flow conveyance conduits 201, 202, and then contains fluid flow 101 ready to be measured through the portholes without needing to extract or divert the fluid flow 101 out of the flow conduits 201, 202.

[0068] The measuring cell 120, shown in Figures 4 to 6, makes it possible to analyze the fluid flow 101 without change in pressure, humidity or temperature. Thus, the measurements are as close as possible to the real conditions of the fluid flow 101 at the inlet or outlet of the fuel cell. The measuring cell 120 has a very small footprint on the flow conduits 201, 202.

[0069] In a first embodiment, the inlet opening of the measuring cell 120 is connected to a conduit for conveying fluid in flow at the outlet of the electrochemical generator system 200.

[0070] In a second embodiment, the outlet opening is connected to a fluid flow conduit at the inlet of the electrochemical generator system 200.

[0071] Thus, the measuring cell can be connected for example to the output or to the input of the electrochemical generator system 200 in order to study the incoming fluids or the fluids exiting the electrochemical generator system 200.

[0072] The first porthole 123 comprises a first glass blade 125 and the second porthole 124 comprises a second glass blade 126.

[0073] The glass slides 125, 126 are preferably made from a borosilicate or aluminosilicate glass or an alkali-aluminosilicate glass. For example, the glass slides 125, 126 are here made with BK7 or with Gorilla Glass. Preferably, the glass slides 125, 126 do not have a surface coating on the face in contact with the flowing fluid 101. The composition and arrangement of the glass slides 125, 126 makes it possible to avoid any degassing or contamination of the flowing fluid, by interaction between the flowing fluid and such a surface coating, which could pollute the measurement.

[0074] The portholes 123, 124 are sealed by the use of seals. The measuring cell 120 comprises, for example, two seals 127, 128, a first seal 127 positioned between the first glass plate 125 and the fluid conduit 129, and a second seal 128 between the second glass plate 126 and the fluid conduit 129.

[0075] Just like the material of the glass slides 125, 126, the material of the seals 127, 128 must not pollute the measurement. For this purpose, the seals 127, 128 are manufactured using an inert component. The seals 127, 128 are here manufactured with a fluoroelastomer material (commonly called FKM or viton).

[0076] The glass plates 125, 126 constitute cold spots. These cold spots on the passage of the flowing fluid 101 can cause condensation, in particular if the flowing fluid 101 contains water or water vapor.

[0077] The presence of condensation on the windows 123, 124 risks deteriorating the quality of the measurements, in particular due to a reduction in signal intensity or an increase in optical aberration.

[0078] According to a particular aspect, illustrated in FIG. 7, the measuring cell 120 comprises at least one thermal unit. The thermal unit is configured to maintain the first porthole and / or the second porthole at a temperature greater than or equal to a threshold temperature. Preferably, the measuring cell 120 comprises two thermal units 131 configured to maintain the two portholes 123, 124 at a temperature greater than or equal to the threshold temperature. The thermal units are powered by electrical cables 132.

[0079] The threshold temperature is defined as a function of the temperature of the flowing fluid 101. For example, the flowing fluid 101 is at a temperature of approximately 60°C and the threshold temperature is approximately 70°C. The thermal unit thus makes it possible to prevent the formation of condensation on the portholes 123, 124.

[0080] The optical system 140 is arranged on the path of the excitation light beam 116, between the light source 111 and the first porthole 123. The optical system 140 is configured to focus the excitation light beam 116 into the flowing fluid 101 between the two portholes 123, 124 of the measuring cell 120. For example, the optical system 140 is a lens or an objective. The second porthole 124 transmits the first light beam 117, formed by diffusion and / or simple transmission of the excitation light beam 116 through the flowing fluid 101, towards the optical device 130.

[0081] The optical device 130 is at least partially reflective. Preferably, the optical device 130 is a concave mirror. The optical device 130 is for example a spherical mirror arranged so that its center of curvature is on the main optical axis OA, in the middle between the two glass plates 123, 124.

[0082] The optical device 130 is positioned to receive the first light beam 117 transmitted by the second porthole 124. The reflective optical device 130 is positioned outside the measuring cell 120. This arrangement avoids any interaction between the flowing fluid 101 and a reflective coating, for example metallic, of the optical device 130, which makes it possible to avoid polluting the flowing fluid 101.

[0083] The optical device 130 is configured to reflect the first light beam 117 and form a reflected light beam 118 toward the flowing fluid 101 through the second porthole 124. The optical device 130 is configured to focus the reflected light beam 118 into the measuring cell between the two portholes. For example, the optical device 130 comprises a spherical mirror, preferably arranged to focus the reflected light beam 118 into the flowing fluid 101, in the middle between the two portholes 123, 124.

[0084] After passing through the flowing fluid 101 and the first porthole 123, a second light beam 119 is obtained, formed by diffusion and / or double transmission of the excitation light beam 116 through the flowing fluid 101 and the portholes 123, 124. The second light beam 119 propagates towards the optical system 140, which makes it possible to collect the second light beam 119.

[0085] The association of the double-pass measuring cell 120 with the reflecting optical device 130 allows double excitation of the flowing fluid 101. Indeed, the excitation beam having passed through the measuring cell 120 is refocused in the flowing fluid 101 and allows the excitation to be doubled. This optical configuration also has the advantage of doubling the solid collection angle by collecting the part of the Raman signal emitted towards the Raman spectrometry device but also that emitted towards the optical device 130 which is then reflected and returned towards the Raman spectrometry device 110.

[0086] The term double pass is related to the round trip path of the light beam in the measuring cell 120. However, the flowing fluid 101 only passes through the measuring cell 120 once, in the direction of flow, without interruption of the flow.

[0087] The Raman spectrometer 112 includes a detection system 113 and a processing system 114. The Raman spectrometer 112 is configured to receive the second light beam 119 comprising the Raman signals emitted by the flowing fluid 101.

[0088] Preferably, the Raman spectrometer 112 is external to the interface box 115, which forms a local probe, and is connected to this local probe via a fiber optic cable FO. S as illustrated in Figures 1 and 4.

[0089] Alternatively, the Raman spectrometer 112 is integrated into the interface box 115.

[0090] In order to avoid pollution of the measurement by air, the optical device 130 and the optical system 140 are positioned as close as possible to the measuring cell 120 in order to reduce the optical path of the light beams.

[0091] For the same reason, the external box 115 collecting the signal is positioned as close as possible to the optical system 140.

[0092] The Raman spectrometer 112 is adapted to detect, in the second light beam 119, a Raman signal emitted by the flowing fluid 101. The Raman signal is emitted in particular thanks to the excitation of the flowing fluid 101 by the excitation light beam 116 and by the reflected light beam 118.

[0093] The Raman spectrometer 112 generally comprises a diffraction grating and a light sensor 113.

[0094] The diffraction grating, for example, is formed of straight, parallel, and regularly spaced lines. The diffraction grating, for example, is a reflective grating positioned to receive and reflect the light beam entering the Raman spectrometer 112, and form a light beam diffracted into different wavelengths of the spectrum.

[0095] The diffracted light beam is usually focused onto the light sensor 113 using the diffraction grating or using an optical focusing system such as a mirror or lens.

[0096] The light sensor 113 comprises, for example, pixels arranged in one or more lines.

[0097] The pixel rows are generally oriented in the spectral diffraction direction of the diffracted light beam image. Preferably, each row comprises the same number of pixels arranged in a column so that the pixels form a matrix on the light sensor.

[0098] Alternatively, the Raman spectrometry apparatus 110 comprises a second light source capable of emitting a second excitation light beam, and the light sensor is configured to simultaneously detect the Raman signal 119 induced by the light source and a second Raman signal emitted by the flowing fluid 101 when the flowing fluid 101 is excited by the second light source.

[0099] The processing system 114 is adapted to deduce a measurement of at least one chemical component of the flowing fluid 101 from the Raman signal detected by the detection system 113.

[0100] The processing system 114 makes it possible to read the light sensor and to deduce at least one spectrum. The at least one spectrum is for example obtained by summing a part of the pixels of the same column.

[0101] Preferably the Raman spectrometry device allows acquisition of a spectrum every second in order to be able to monitor the flowing fluid 101 in real time.

[0102] Figure 9 shows an example of a Raman spectrum thus measured. In the Raman spectrum of Figure 9, an intensity I of the measured signal is represented as a function of the Raman shift ûw (in cm -1 ). The measured signal has a peak at approximately 2300 cm -1 corresponding to nitrogen. The measured signal shows another peak at approximately 4100 cm -1 corresponding to dihydrogen.

[0103] The intensity of the measured Raman signal depends on the concentration of the elements present, the pressure value and the power of the excitation beam. The processing system 114 is configured to calculate the concentration of the chemical components sought using the measured signal and using a calibration function. The calibration function makes it possible to establish a function between the measured Raman signal of a chemical component and the concentration of this chemical component.

[0104] A calibration function to convert the measured signal intensity into hydrogen concentration is shown in Figure 8.

[0105] The calibration function is determined, for example, by measuring a standard fluid at given concentrations.

[0106] For example, in Figure 10, a fluid comprising dihydrogen at a predetermined and variable concentration was measured by the measuring system 100. The measured signal comprises several plateaus each corresponding to a different concentration. The dihydrogen concentration corresponding to the plateau between time t=0 and time t approximately 308 s., is equal to 0%. The dihydrogen concentration corresponding to the plateau between time t approximately 308 s. and time t approximately 400 s., is equal to 2%. The dihydrogen concentration corresponding to the plateau between time t approximately 400 s. and time t approximately 520 s., is equal to 5%. The dihydrogen concentration corresponding to the plateau between time t approximately 520 s. and time t approximately 610 s., is equal to 10%. The dihydrogen concentration corresponding to the plateau between time t approximately 610 s. and the instant t approximately 710 s., is equal to 20%.The hydrogen concentration corresponding to the plateau between time t about 710 s. and time t about 810 s., is equal to 60%. The hydrogen concentration corresponding to the plateau between time t about 810 s. and time t about 910 s., is equal to 80%. The hydrogen concentration corresponding. at the plateau between time t approximately 910 s. and time t approximately 1000 s., is equal to 100%. The curve thus represents the intensity of a Raman signal for a fluid comprising a concentration between 0 and 100% of dihydrogen.

[0107] This curve allows the calibration function presented in figure 8 to be established.

[0108] This curve also allows the measurement accuracy to be established. For the example shown in Figure 10, a measurement accuracy of approximately 5% is observed. The 100 measurement system allows an accuracy of up to 0.2% to be obtained.

[0109] The calibration function can also take into account the aging of the measuring system 100 such as a decrease in the intensity of the light source 111 or a decrease in the transmission of the components used (portholes 123, 124, optical device 130 and optical system 140). In general, the calibration function is updated at regular intervals or when this seems necessary.

[0110] The measurement system 100 also allows for detecting polluting chemical components. For example, the processing system 114 is configured to detect signals in the spectrum that do not correspond to the expected chemical elements in the flowing fluid 101.

[0111] For example, the intensity of the Raman signal corresponding to dihydrogen and dinitrogen is measured simultaneously as a function of time. Monitoring the evolution of the Raman signal as a function of time makes it possible to monitor and record the various events occurring in the electrochemical generator system 200 of the fuel cell type, in particular a hydrogen cell generating electricity. The events may include load increases, fluctuations in the supply of fluid or even the discharging of the electrochemical generator system 200.

[0112] Figure 11 illustrates a multi-point measurement system based on the use of several measuring cells. Such a measurement system makes it possible to simultaneously measure the chemical composition of at least one fluid at several inlet and / or outlet points of an electrochemical generator system comprising a plurality of inlet and / or outlet fluid conduits 201. The multi-point measurement system applies in particular to a fuel cell or an electrolyzer. For example, a fuel cell comprises two fluid inlet conduits 201: one inlet conduit 201 being adapted for the injection of air and another inlet conduit 201 being adapted for the injection of dihydrogen. The fuel cell also comprises two fluid outlet conduits 201: one outlet conduit 201 on the anode, the other outlet conduit 201 on the cathode of the fuel cell.

[0113] For this purpose, the measuring system comprises a plurality of double-pass measuring cells 1201, 1202, 1203, 1204 each arranged on a fluid conduit 201. input or output of the electrochemical generator system. The plurality of measuring cells comprises two, three, four or more measuring cells. In one example, the measuring system comprises a measuring cell 1201 on an output conduit 201 and another measuring cell 1202 on another output conduit 201. In one example, the measuring system comprises a measuring cell 1201 on an output conduit 201 and another measuring cell 1203 on a dihydrogen inlet conduit 201. In another example, the measuring system comprises a measuring cell 1201 on an output conduit 201 and another measuring cell 1203 on an oxygen inlet conduit 201. In another example, the measuring system comprises a measuring cell 1203 on a dihydrogen inlet conduit 201 and another measuring cell 1204 on an oxygen inlet conduit 201.In yet another example, the measurement system comprises a measurement cell 1203 on a dihydrogen inlet conduit 201, another measurement cell 1204 on an oxygen inlet conduit 201, a measurement cell 1201 on an outlet conduit 201 and another measurement cell 1202 on another outlet conduit 201. A controller makes it possible to activate the measurement of several measurement cells among the measurement cells installed on the conduits.

[0114] The multi-point measurement system also comprises a Raman spectrometry apparatus 110 comprising a light source 111, a Raman spectrometer 112 comprising a detection system 113 and a processing system 114. The light source 111 is configured to generate an excitation light beam 116. Advantageously, a beam splitter is arranged to receive the excitation light beam 116 and form a plurality of divided excitation light beams. For example, a beam splitter is used. Each divided excitation light beam is directed, for example by optical fiber, towards a measurement cell among the plurality of measurement cells. This configuration makes it possible to use the same light source 111 for the measurements of the plurality of measurement cells, all operating at the same source wavelength.Alternatively, several light sources are used, each light source generating an excitation light beam directed towards a measuring cell.

[0115] Each measuring cell 1201, 1202, 1203, 1204 is configured as described above, for example in connection with FIG. 3 on a specific inlet or outlet conduit of the electrochemical generator system. Each measuring cell 1201, 1202, 1203, 1204 is adapted to receive a split excitation light beam and transmit a first light beam formed by diffusion and / or simple transmission of the split excitation light beam through the flowing fluid 101 in the fluid conduit considered. As described above, the at least partially reflective optical device 130 of each fluid cell is positioned to receive the first light beam transmitted by the two portholes and configured to reflect the first beam light towards the flowing fluid through the two portholes 123, 124 to form a second light beam formed by diffusion and / or double transmission of the excitation light beam through the flowing fluid 101 and the two portholes 123, 124.

[0116] The Raman spectrometer 112 is configured to separately receive the second light beam from each double-pass measuring cell 1201, 1202, 1203, 1204, for example via optical fiber. Advantageously, the optical fibers carrying the second light beam from each measuring cell 1201, 1202, 1203, 1204 are arranged in line along the elongated direction of the entrance slit of the Raman spectrometer 112. The detection system preferably comprises an imaging detector adapted to separately detect a Raman signal corresponding to each second light beam coming from each measuring cell 1201, 1202, 1203, 1204. The detection system thus makes it possible to separately detect on different areas of the imaging detector the Raman signal emitted by the flowing fluid of each double-pass measuring cell. Advantageously, the detection of the different Raman signals coming from the different measuring cells is simultaneous.The processing system is adapted to deduce therefrom a measurement of at least one chemical component of the fluid flowing in each double-pass measuring cell 1201, 1202, 1203, 1204. Such a multi-point measuring system makes it possible, at low cost, to measure the chemical composition of the fluid at several inlet and / or outlet points of the electrochemical generator system 200. In a particularly advantageous manner, the system comprises as many measuring cells as there are inlet and outlet fluid conduits, which makes it possible to measure simultaneously, in real time and in a non-intrusive manner all the fluid inputs and outputs of the electrochemical generator system 200. Such a system provides information on the operation of the electrochemical generator system 200.

[0117] In particular, in a fuel cell, it is particularly advantageous to have a measuring cell 1203 on the anode-side inlet pipe, a measuring cell 1204 on the cathode-side inlet pipe, a measuring cell 1201 on the anode-side outlet pipe, and a measuring cell 120 on the cathode-side outlet pipe. The measuring cells 1201, 1203 on the inlet and outlet anodes make it possible to monitor the chemical composition of the fluids, in particular hydrogen, nitrogen, water (H2O), carbon dioxide (CO2), and carbon monoxide (CO). The measuring cells 1202, 1204 on the inlet and outlet cathodes make it possible to monitor the chemical composition of the fluids, in particular hydrogen, oxygen, nitrogen, and water (H2O).These measurements, carried out simultaneously and in real time, make it possible to evaluate the efficiency of the fuel cell, to carry out stress measurements on the fuel cell, modeling or simulations, or even improvements to the fuel cell.

[0118] The multi-point measuring system is applied analogously to monitor simultaneously and in real time, in a non-intrusive manner, the fluid inputs and outputs of an electrolyser.

[0119] The present invention is in no way limited to the embodiment described and shown, but those skilled in the art will be able to provide any variation in accordance with the invention.

Claims

CLAIMS 1. Measuring system (100) of at least one chemical component of a flowing fluid (101) for an electrochemical generator system (200), the measuring system comprising: - a Raman spectrometry apparatus (110) comprising a light source (111), a Raman spectrometer (112) comprising a detection system (113) and a processing system (114), the light source (111) being configured to generate an excitation light beam (116), - a double-pass measuring cell (120) comprising a fluid conduit (129) having an inlet opening (121) configured to allow the flowing fluid (101) to enter and an outlet opening (122) configured to allow the flowing fluid (101) to exit, the measuring cell (120) comprising a first sealed porthole (123) and a second sealed porthole (124), the two ports (123, 124) being arranged laterally on the fluid conduit (129) downstream of the inlet opening (121) and upstream of the outlet opening (122), the two ports (123, 124) being positioned opposite each other on a main optical axis transverse to the fluid conduit and configured to receive the excitation light beam and transmit a first light beam formed by diffusion and / or simple transmission of the excitation light beam through the flowing fluid (101), and - an at least partially reflective optical device (130) positioned to receive the first light beam transmitted by the two portholes (123, 124) and configured to reflect the first light beam towards the flowing fluid (101) through the two portholes (123, 124) to form a second light beam (119) formed by diffusion and / or double transmission of the excitation light beam through the flowing fluid (101) and the two portholes (123, 124), the Raman spectrometer (112) being configured to receive the second light beam (119), the detection system (113) being adapted to detect a Raman signal emitted by the flowing fluid (101) and the processing system (114) being adapted to deduce therefrom a measurement of at least one chemical component of the flowing fluid (101).

2. Measuring system (100) according to claim 1, wherein the measuring cell (120) is connected to an output of an electrochemical generator system (200) of the electrolyzer type for the generation of hydrogen and wherein the Raman spectrometry apparatus (110) is adapted to measure the concentration of at least one chemical component among water, nitrogen, hydrogen and oxygen.

3. The measuring system (100) of claim 1, wherein the outlet opening (122) of the measuring cell (120) is connected to an input or an output of an electrochemical generator system (200) of the hydrogen fuel cell type and in which the Raman spectrometry apparatus (110) is adapted to measure the concentration of at least one chemical component among water, nitrogen, hydrogen and oxygen.

4. Measuring system (100) according to one of claims 1 to 3, wherein the inlet opening (121) or the outlet opening (122) of the measuring cell (120) is connected via a conveying conduit (201; 202) of flowing fluid to the electrochemical generator system (200).

5. Measuring system (100) according to claim 4, wherein the section of the inlet opening (121) and the section of the outlet opening (122) of the measuring cell (120) are each greater than or equal to the section of the conveying conduit (201, 202) of flowing fluid of the electrochemical generator system (200).

6. Measuring system (100) according to one of claims 1 to 5, comprising an optical system (140) arranged between the light source (111) and the first porthole (123), the optical system (140) being configured to focus the excitation light beam in the measuring cell (120) between the two portholes (123, 124).

7. Measuring system (100) according to one of claims 1 to 6, wherein the at least partially reflective optical device (130) is configured to reflect and focus the first light beam in the measuring cell (120) between the two portholes (123, 124).

8. Measuring system (100) according to one of claims 1 to 7, wherein the measuring cell (120) comprises at least one thermal unit (131) configured to maintain the first window (123) and / or the second window (124) at a temperature greater than or equal to a threshold temperature.

9. Measuring system (100) according to one of claims 1 to 8, in which the first porthole (123) comprises a first glass slide and the second porthole (124) comprises a second glass slide, wherein the first, respectively second, glass slide is made from one of a borosilicate glass or an alkali-aluminosilicate glass.

10. Measuring system (100) according to one of claims 1 to 9, comprising a second measuring cell and in which the Raman spectrometry apparatus (110) comprises a second light source capable of emitting a second beam excitation light beam, the detection system (113) comprises a light sensor having pixels arranged in several rows and configured to simultaneously detect the Raman signal induced by the light source (111) and a second Raman signal emitted by the flowing fluid (101) when the flowing fluid (101) is excited by the second excitation light beam.

11. System for measuring at least one chemical component of a flowing fluid (101) for an electrochemical generator system (200) comprising a plurality of inlet and / or outlet fluid conduits (201), the measuring system comprising - a Raman spectrometry apparatus (110) comprising a light source (111), a Raman spectrometer (112) comprising a detection system (113) and a processing system (114), the light source (111) being configured to generate an excitation light beam (116), a beam splitter arranged to receive the excitation light beam (116) and form a plurality of divided excitation light beams, - a plurality of double-pass measuring cells (1201, 1202, 1203, 1204) each arranged on an inlet or outlet fluid conduit (201) of the electrochemical generator system, each double-pass measuring cell (1201, 1202, 1203, 1204) comprising a fluid conduit (129) having an inlet opening (121) configured to allow the fluid to flow in from said inlet or outlet fluid conduit (201) of the electrochemical generator system (200) and an outlet opening (202) configured to allow the fluid to flow out, each measuring cell (1201, 1202, 1203, 1204) comprising a first sealed porthole (123) and a second sealed porthole (124), the two ports (123, 124) of each measuring cell (1201 , 1202, 1203, 1204) being arranged laterally on the fluid conduit downstream of the inlet opening and upstream of the outlet opening, the two portholes (123, 124) of each measuring cell (1201, 1202, 1203,1204) being positioned opposite each other on a main optical axis transverse to the fluid conduit and configured to receive a divided excitation light beam and transmit a first light beam formed by diffusion and / or simple transmission of the divided excitation light beam through the flowing fluid (101) in the fluid conduit, and, - an optical device (130) at least partially reflecting positioned to receive the first light beam transmitted by the two portholes and configured to reflect the first light beam towards the fluid in flow through the two portholes (123, 124) to form a second light beam formed by diffusion and / or double transmission of the excitation light beam through the flowing fluid (101) and the two portholes (123, 124), the Raman spectrometer (112) being configured to receive separately from each measuring cell (1201, 1202, 1203, 1204) double pass the second light beam, the detection system being adapted to separately detect a signal Raman emitted by the fluid in flow of each double-pass measuring cell and the processing system being adapted to deduce therefrom a measurement of at least one chemical component of the fluid in flow in each double-pass measuring cell (1201, 1202, 1203, 1204).

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