Measurement system

Abstract

This measurement system aims to suppress the deterioration of component parts, even when measuring liquids. [Solution] The fuel cell cell 2 has a hydrogen electrode E1, an air electrode E2, and an electrolyte 24b, a hydrogen electrode separator 3 that supplies hydrogen to the hydrogen electrode E1, and a measuring device that measures the amount of electrical energy generated in the fuel cell cell 2. The hydrogen electrode separator 3 has a stirring chamber 32 in which the liquid to be measured is stirred, a guide chamber 33 that guides the hydrogen separated from the liquid in the stirring chamber 32 to the hydrogen electrode E1, and a separation membrane 34 that is placed at the boundary between the stirring chamber 32 and the guide chamber 33 and allows hydrogen to permeate but does not allow liquid to permeate.

Description

Technical Field

[0001] The present invention relates to a measurement system.

Background Art

[0002] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The measurement system according to the present invention comprises a fuel cell cell having a hydrogen electrode, an air electrode, and an electrolyte; a hydrogen electrode separator that supplies hydrogen to the hydrogen electrode; and a measuring device for measuring the amount of electrical energy generated in the fuel cell, wherein the hydrogen electrode separator has a stirring chamber in which the liquid to be measured is stirred; a guide chamber that guides the hydrogen separated from the liquid in the stirring chamber to the hydrogen electrode; and a separation membrane disposed at the boundary between the stirring chamber and the guide chamber, which allows the permeation of hydrogen but does not allow the permeation of the liquid.

[0008] This configuration allows for the evaluation of hydrogen contained in the liquid being measured by measuring the amount of electrical energy generated in the fuel cell. Furthermore, because the hydrogen electrode separator has a separation membrane, contact between the liquid and the fuel cell can be prevented, thus reducing the degradation of components such as catalysts.

[0009] Preferred embodiments of the present invention will be described below. However, the scope of the present invention is not limited by the examples of preferred embodiments described below.

[0010] In one embodiment, the measurement system according to the present invention preferably comprises at least one material selected from the group consisting of polytetrafluoroethylene, fluorinated ethylene propylene copolymer, silicone, polyethylene, polypropylene, polystyrene, polyurethane, cellulose acetate, polyacrylonitrile, and polyetheretherketone.

[0011] This configuration makes it easier to achieve both preventing liquid from entering the fuel cell and guiding hydrogen into the fuel cell.

[0012] In one embodiment, the measurement system according to the present invention preferably includes at least one membrane selected from the group consisting of porous membranes and gas permeable membranes.

[0013] This configuration makes it easier to achieve both preventing liquid from entering the fuel cell and guiding hydrogen into the fuel cell.

[0014] In one embodiment, the measurement system according to the present invention preferably further comprises a separation membrane-side sealing member disposed between the hydrogen electrode and the separation membrane.

[0015] This configuration prevents hydrogen from permeating through gaps around the separation membrane, ensuring that all hydrogen contained in the water being measured is supplied to the hydrogen electrode without leakage, thus improving measurement accuracy.

[0016] In one embodiment, the measurement system according to the present invention preferably further includes an electrolyte-side sealing member disposed between the hydrogen electrode and the electrolyte in the fuel cell cell.

[0017] This configuration prevents hydrogen from permeating through gaps around the hydrogen electrode, ensuring that all hydrogen contained in the water being measured is supplied to the electrode without leakage, thus improving measurement accuracy.

[0018] In one embodiment, the measurement system according to the present invention preferably further comprises a hydrogen electrode separator comprising at least a housing that houses the separation membrane and defines the stirring chamber and the guide chamber, and a housing-side sealing member disposed between the housing and the separation membrane.

[0019] This configuration makes it particularly easy to prevent liquid from entering the fuel cell.

[0020] Further features and advantages of the present invention will become clearer through the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0021] [Figure 1] This is a cross-sectional view of the measurement system according to this embodiment. [Figure 2] This is a partially exploded perspective view of the measurement system according to this embodiment. [Figure 3] This figure shows the electrical circuit of the measurement system according to this embodiment.

Embodiment for Carrying out the Invention

[0022] An embodiment of the measuring device according to the present invention will be described with reference to the drawings. Hereinafter, an example in which the measuring device according to the present invention is applied to a measuring system 1 for measuring the dissolved hydrogen concentration of water (an example of a liquid to be measured) to be measured will be described.

[0023] 〔Configuration of Measuring Device〕 The measuring system 1 according to the present embodiment includes a fuel cell 2, a hydrogen electrode separator 3 that supplies hydrogen to the fuel cell 2, an air electrode separator 4 that supplies air to the fuel cell 2, a measuring device 5 that measures the amount of electrical energy generated in the fuel cell 2, and a calculation device 6 that calculates the dissolved hydrogen concentration of the water to be measured based on the measurement value of the measuring device 5 (FIGS. 1 to 3). The fuel cell 2 is housed in a housing 7. A hydrogen electrode separator 3 is formed on one side of the housing 7, and an air electrode separator 4 is formed on the other side of the housing 7.

[0024] The measuring system 1 is generally a device that supplies hydrogen dissolved in the water to be measured to the hydrogen electrode E1 of the fuel cell 2 to generate electrical energy, and measures the dissolved hydrogen concentration of the water to be measured through the measurement of the amount of the electrical energy.

[0025] The hydrogen electrode separator 3 has a sample inlet 31, a stirring chamber 32, a guiding chamber 33, a separation membrane 34, a sample outlet 35, a separation membrane side sealing member 36, and a housing side sealing member 37. The stirring chamber 32 and the guiding chamber 33 are defined as spaces inside the housing 7. Therefore, the housing 7 is a component of the hydrogen electrode separator 3.

[0026] The water to be measured is introduced into the stirring chamber 32 through the sample inlet 31 and stirred in the stirring chamber 32. The stirring in the stirring chamber 32 causes dissolved hydrogen in the water to detach, permeate the separation membrane 34, and enter the guide chamber 33. The guide chamber 33 is in contact with the hydrogen electrode E1 of the fuel cell cell 2, and therefore the hydrogen that enters the guide chamber 33 is guided to the hydrogen electrode E1. The water, separated from the hydrogen, is discharged from the stirring chamber 32 through the sample outlet 35 to the outside of the system.

[0027] The stirring chamber 32 is provided with multiple stirring columns 32a. Because the stirring chamber 32 has multiple stirring columns 32a, the water introduced from the sample inlet 31 follows a complex path before being discharged from the sample outlet 35, colliding with the stirring columns 32a along the way. These collisions create turbulence in the water flow, stirring the water and causing dissolved hydrogen to detach. In this embodiment, the stirring columns 32a are formed as part of the housing 7.

[0028] The separation membrane 34 is positioned at the boundary between the stirring chamber 32 and the guide chamber 33. In other words, the stirring chamber 32 and the guide chamber 33 are two spaces formed in the housing 7 and divided into two spaces by the separation membrane 34. The separation membrane 34 allows hydrogen permeation but not water permeation. From the viewpoint of achieving such selective permeability, the separation membrane 34 preferably contains at least one material selected from the group consisting of polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), silicone, polyethylene, polypropylene, polystyrene, polyurethane, cellulose acetate, polyacrylonitrile, and polyether ether ketone (PEEK), and more preferably contains at least one material selected from the group consisting of polytetrafluoroethylene (PTFE) and silicone. Examples of membranes that achieve such selective permeability include porous membranes and gas permeable membranes. Therefore, the separation membrane 34 may be a porous membrane or a gas permeable membrane made of the materials exemplified above, for example, a porous membrane made of polytetrafluoroethylene or a gas permeable membrane made of silicone. However, the combination of material types and membrane types exemplified above is arbitrary. The presence of the separation membrane 34 makes it easier to prevent water from entering the hydrogen electrode E1.

[0029] The separation membrane-side sealing member 36 is a member positioned between the separation membrane 34 and the hydrogen electrode plate 21 (hydrogen electrode E1) of the fuel cell cell 2, and plays a role in preventing hydrogen from permeating through the gap between the separation membrane 34 and the hydrogen electrode plate 21. By preventing hydrogen from permeating through this gap, hydrogen separated from the water being measured can be quantitatively supplied to the hydrogen electrode E1, thereby improving measurement accuracy. The separation membrane-side sealing member 36 may include films such as polyimide, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF), polyvinyl alcohol, polypropylene, polyvinylidene chloride, polyethylene terephthalate, and ethylene vinyl alcohol copolymer. It is preferable that the separation membrane-side sealing member 36 be in the form of an adhesive tape with an adhesive applied to one of the above films, as this facilitates the assembly of the measurement system 1.

[0030] The housing-side sealing member 37 is positioned between the separation membrane 34 and the housing 7, and its role is to prevent the water to be measured from flowing into the guide chamber 33 by passing around the separation membrane 34. By preventing water from flowing into the guide chamber 33, it is easier to avoid the problem of the catalyst of the fuel cell cell 2 becoming wet and losing its activity. The housing-side sealing member 37 can be made of materials such as polytetrafluoroethylene (PTFE), silicone, nitrile rubber, ethylene propylene rubber, chloroprene rubber, polyurethane, or fluororubber.

[0031] The air electrode separator 4 has an inlet / outlet 41 and a diffusion chamber 42. The diffusion chamber 42 is defined as the space inside the housing 7. Therefore, the housing 7 is a component of the air electrode separator 4.

[0032] In the air electrode E2 of fuel cell cell 2, a reaction occurs that produces water from oxygen in the air supplied to the air electrode E2 and hydrogen ions and electrons that have moved from the hydrogen electrode E1 to the air electrode E2. The air electrode separator 4 plays the role of supplying oxygen (air) to the air electrode E2 to participate in this reaction and discharging the water produced by this reaction to the outside of the system. The air enters the diffusion chamber 42 through the inlet / outlet 41, diffuses in the diffusion chamber 42, and then reaches the air electrode E2. The water produced in the air electrode E2 is discharged as water vapor from the inlet / outlet 41 to the outside of the system.

[0033] The fuel cell cell 2 comprises a hydrogen electrode plate 21, a hydrogen electrode gas diffusion layer 22, an electrolyte-side sealing member 23, a membrane electrode assembly 24, an air electrode gas diffusion layer 25, and an air electrode plate 26. The membrane electrode assembly 24 may be a membrane electrode assembly (MEA) known in the field of fuel cell technology, and includes a hydrogen electrode catalyst layer 24a, an electrolyte 24b, and an air electrode catalyst layer 24c. The hydrogen electrode plate 21, the hydrogen electrode gas diffusion layer 22, and the hydrogen electrode catalyst layer 24a constitute the hydrogen electrode E1 to which hydrogen is supplied, and the air electrode plate 26, the air electrode gas diffusion layer 25, and the air electrode catalyst layer 24c constitute the air electrode E2 to which air is supplied.

[0034] The hydrogen electrode plate 21 is a plate-shaped member made of a conductive material. Examples of such conductive materials include metals such as brass, stainless steel (SUS304, SUS316, etc.), and steel (SS400, SS490, etc.), as well as sintered materials made from these metals and carbon, but are not limited to these. The hydrogen electrode plate 21 is also provided with a plurality of through holes 21a. The hydrogen electrode plate 21 is connected to the air electrode plate 26 via a measuring device 5.

[0035] The hydrogen electrode gas diffusion layer 22 is the portion that serves as a pathway for hydrogen supplied to the hydrogen electrode E1 to reach the membrane electrode assembly 24 (hydrogen electrode catalyst layer 24a). The hydrogen electrode gas diffusion layer 22 is a conductive material that allows hydrogen to permeate, and may be, but is not limited to, a membrane material such as carbon fiber, graphite sheet, carbon nanotube, or carbon black mixed material. The hydrogen electrode gas diffusion layer 22 may be a single membrane material or a combination (overlapping) of multiple membrane materials.

[0036] The electrolyte-side sealing member 23 is a member positioned between the hydrogen electrode plate 21 and the membrane electrode assembly 24, and plays a role in preventing hydrogen from permeating through the gap between the hydrogen electrode plate 21 and the membrane electrode assembly 24. By preventing hydrogen from permeating through this gap, hydrogen released from the water being measured can be quantitatively supplied to the hydrogen electrode catalyst layer 24a, thereby improving measurement accuracy. The electrolyte-side sealing member 23 is a rectangular sheet-like member with a hollowed-out central portion, and the hydrogen electrode gas diffusion layer 22 is positioned in the hollowed-out portion.

[0037] The air electrode plate 26 is a plate-shaped member made of a conductive material. Examples of such conductive materials include, but are not limited to, metals such as brass, stainless steel (SUS304, SUS316, etc.), and steel (SS400, SS490, etc.), or materials obtained by sintering these metals with carbon. The air electrode plate 26 is also provided with a plurality of through holes 26a. The air electrode plate 26 is connected to the hydrogen electrode plate 21 via the measuring device 5.

[0038] The air electrode gas diffusion layer 25 is the portion that serves as the path for air supplied to the air electrode E2 to reach the membrane electrode assembly 24 (air electrode catalyst layer 24c). The air electrode gas diffusion layer 25 is a conductive material that allows air to pass through, and may be, but is not limited to, a membrane material such as carbon fiber, graphite sheet, carbon nanotube, or carbon black mixed material. It is preferable that the air electrode gas diffusion layer 25 is at least partially water-repellent, as this facilitates the discharge of water generated in the air electrode E2 from the fuel cell cell 2 system. Examples of materials that can impart water repellency to the air electrode gas diffusion layer 25 include, but is not limited to, fluororesin. The air electrode gas diffusion layer 25 may be a single membrane material or a combination (overlapping) of multiple membrane materials.

[0039] In the hydrogen electrode catalyst layer 24a, the reaction shown in equation (1) occurs, generating hydrogen ions and electrons from the hydrogen supplied to the hydrogen electrode E1. H2→2H + +e - (1) Hydrogen ions move through the electrolyte 24b to the air electrode catalyst layer 24c. Electrons reach the air electrode catalyst layer 24c via the hydrogen electrode gas diffusion layer 22, hydrogen electrode plate 21, measuring device 5, air electrode plate 26, and air electrode gas diffusion layer 25 in that order.

[0040] In the air electrode catalyst layer 24c, the reaction shown in equation (2) occurs, producing water from oxygen in the air supplied to the air electrode E2 and hydrogen ions and electrons that have moved from the hydrogen electrode E1 side to the air electrode E2 side. 2H + +2e - +(1 / 2)O2→H2O (2)

[0041] The measuring device 5 is a device for measuring the amount of electrical energy generated in the fuel cell cell 2. Specifically, it measures the current, voltage, power consumption, etc., between the hydrogen electrode plate 21 and the air electrode plate 26, and determines the amount of electrical energy generated through these measurements. In other words, the measuring device 5 may include measuring instruments 51 such as an ammeter, voltmeter, and power consumption meter, and an electrical circuit 52 that connects such measuring instruments to the hydrogen electrode plate 21 and the air electrode plate 26. Figure 3 shows an example where the measuring instrument 51 is a voltmeter, and in this example, the electrical circuit 52 has a short-circuit resistor 53 between the hydrogen electrode plate 21 and the air electrode plate 26.

[0042] The amount of electrical energy generated in fuel cell 2 is positively correlated with the amount of hydrogen supplied to hydrogen electrode E1. Furthermore, the amount of hydrogen supplied to hydrogen electrode E1 is positively correlated with the amount of dissolved hydrogen in the water being measured. Therefore, the measurement system 1 can measure the dissolved hydrogen concentration of the water being measured by measuring the amount of electrical energy generated in fuel cell 2.

[0043] The calculation device 6 is a device that calculates the dissolved hydrogen concentration of the water to be measured based on the measurement values ​​from the measuring device 5. The calculation device 6 may be a known device capable of performing calculations, such as a personal computer or a microcontroller. In addition, there is no preclude considering factors other than the measurement values ​​from the measuring device 5, i.e., factors other than the amount of electrical energy generated in the fuel cell cell 2, when calculating the dissolved hydrogen concentration, and in this case, the measurement system 1 may be equipped with the devices necessary to identify such factors.

[0044] The following explanation will describe an example where the measuring device 5 measures the amount of electrical energy generated in the fuel cell 2 as a voltage value. The voltage generated in the fuel cell 2 is proportional to the dissolved hydrogen concentration of the water being measured. Therefore, if this proportional relationship is stored in the calculation device 6 beforehand, the dissolved hydrogen concentration can be calculated from the voltage measured by the measuring device 5.

[0045] Furthermore, through diligent research by the inventors, it has become clear that the proportional relationship between the voltage generated in the fuel cell cell 2 and the dissolved hydrogen concentration of the water being measured is temperature-dependent. Therefore, the effect of temperature may be taken into consideration in the calculation process that calculates the dissolved hydrogen concentration from the voltage measured by the measuring device 5. In this case, the measuring system 1 is equipped with a thermometer (not shown) for measuring the water temperature. The dissolved hydrogen concentration C [mg / L] is expressed by the following equation (3), with the voltage E [V] measured by the measuring device 5 and the temperature T [°C] measured by the thermometer as variables.

number

[0046] In equation (3), p, q, and r are constants and depend on the configuration of the measurement system 1. For example, when the short-circuit resistor 53 is a resistive element with a resistance of 33Ω, p is 0.08, q is 0.006, and r is 0.14.

[0047] It should be noted that it may take some time for the voltage generated in the fuel cell cell 2 to stabilize after the water to be measured is supplied to the hydrogen electrode separator 3. Therefore, it is preferable to calculate the dissolved hydrogen concentration after confirming that the voltage measured by the measuring device 5 has stabilized. For example, when the water temperature is 15°C, it took approximately 130 seconds from the flow of water to the hydrogen electrode separator 3 until the voltage stabilized, so it is considered preferable to allow a stabilization time of about 3 to 5 minutes after the water is supplied before taking the measurement.

[0048] The material of the housing 7 is not limited, as long as it has sufficiently lower conductivity than the hydrogen electrode plate 21 and the air electrode plate 26, and its permeability to hydrogen gas is low enough to be practical. The material of the housing 7 may be, but is not limited to, acrylic resin, ABS resin, polypropylene resin, polyethylene resin, etc.

[0049] [Other Embodiments] Finally, other embodiments of the measurement system according to the present invention will be described. Note that the configurations disclosed in each of the following embodiments can be applied in combination with configurations disclosed in other embodiments, as long as this does not create a contradiction.

[0050] In the above embodiment, an example was described in which, in the fuel cell cell 2, the hydrogen electrode plate 21, the hydrogen electrode gas diffusion layer 22, and the hydrogen electrode catalyst layer 24a constitute the hydrogen electrode E1 to which hydrogen is supplied, and the air electrode plate 26, the air electrode gas diffusion layer 25, and the air electrode catalyst layer 24c constitute the air electrode E2 to which air is supplied. However, in the present invention, the specific configuration of the hydrogen electrode and the air electrode is arbitrary. For example, instead of the membrane electrode assembly 24 in the above embodiment, the hydrogen electrode catalyst layer, the electrolyte, and the air electrode catalyst layer may each be separate components. Also, for example, one or both of the hydrogen electrode gas diffusion layer and the air electrode gas stirring layer may be omitted.

[0051] In the above embodiment, a configuration in which the fuel cell cell 2 has an electrolyte-side sealing member 23 was described as an example. However, in the present invention, the presence or absence of the electrolyte-side sealing member is optional.

[0052] In the above embodiment, a configuration in which the hydrogen electrode separator 3 has a separation membrane side sealing member 36 was described as an example. However, in the present invention, the presence or absence of the separation membrane side sealing member is optional.

[0053] In the above embodiment, a configuration in which the hydrogen electrode separator 3 has a housing-side sealing member 37 was described as an example. However, in the present invention, the presence or absence of the housing-side sealing member is optional.

[0054] In the above embodiment, a configuration was described as in which the fuel cell cell 2 is housed in a housing 7, and the hydrogen electrode separator 3 and the air electrode separator 4 are defined as the space inside the housing 7. However, the housing is not an essential component in the present invention, and even when a housing is provided, its configuration is not limited to the above embodiment. For example, a configuration in which separate housings are provided for each of the fuel cell cell, the hydrogen electrode separator, and the air electrode separator can also be adopted as a configuration of the present invention.

[0055] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the invention. Therefore, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention. [Industrial applicability]

[0056] This invention can be used, for example, to measure the dissolved hydrogen concentration in hydrogen water. [Explanation of Symbols]

[0057] 1: Measurement System 2: Fuel cell 21: Hydrogen electrode plate 22: Hydrogen electrode gas diffusion layer 23: Electrolyte-side sealing member 24: Membrane electrode assembly 24a: Hydrogen electrode catalyst layer 24b: Electrolyte 24c: Air electrode catalyst layer 25: Air electrode gas diffusion layer 26: Air electrode plate E1: Hydrogen electrode E2: Air pole 3: Hydrogen electrode separator 31: Sample Inlet 32: Stirring chamber 32a: Stirring column 33: Information Room 34: Separation membrane 35: Sample outlet 36: Separation membrane side sealing member 37: Housing-side sealing member 4: Air electrode separator 41: Entrance / exit 42: Diffusion chamber 5: Measuring device 51: Measuring equipment 52: Electrical Circuits 53: Short-circuit resistance 6: Computing device 7: Housing

Claims

1. A fuel cell having a hydrogen electrode, an air electrode, and an electrolyte, A hydrogen electrode separator that supplies hydrogen to the aforementioned hydrogen electrode, The system includes a measuring device for measuring the amount of electrical energy generated in the fuel cell, The hydrogen electrode separator is, A stirring chamber in which the liquid to be measured is stirred, A guide chamber for guiding hydrogen separated from the liquid in the stirring chamber to the hydrogen electrode, A measuring system comprising a separation membrane positioned at the boundary between the stirring chamber and the guide chamber, which allows hydrogen permeation but prevents the permeation of the liquid.

2. The measurement system according to claim 1, wherein the separation membrane comprises at least one material selected from the group consisting of polytetrafluoroethylene, fluorinated ethylene propylene copolymer, silicone, polyethylene, polypropylene, polystyrene, polyurethane, cellulose acetate, polyacrylonitrile, and polyetheretherketone.

3. The measurement system according to claim 1, wherein the separation membrane comprises at least one membrane selected from the group consisting of porous membranes and gas permeable membranes.

4. The measurement system according to claim 1, further comprising a separation membrane side sealing member disposed between the hydrogen electrode and the separation membrane of the hydrogen electrode separator.

5. The measurement system according to claim 1, further comprising an electrolyte-side sealing member disposed between the hydrogen electrode and the electrolyte in the fuel cell cell.

6. The hydrogen electrode separator is, A housing comprising at least the separation membrane and defining the stirring chamber and the guide chamber, The measurement system according to any one of claims 1 to 5, further comprising a housing-side sealing member disposed between the housing and the separation membrane.

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