WO2008062561A1

WO2008062561A1 - Measuring device, fuel battery with same, and measuring method

Info

Publication number: WO2008062561A1
Application number: PCT/JP2007/001283
Authority: WO
Inventors: Kuniyasu Ogawa; Tomoyuki Haishi; Kohei Ito
Original assignee: Keio University
Priority date: 2006-11-22
Filing date: 2007-11-21
Publication date: 2008-05-29
Also published as: JP5046203B2; JP2008128883A

Abstract

A measuring device (100) locally measures the amount of protic solvent at a specific region in a membrane (115) by the nuclear magnetic resonance method. The measuring device (100) comprises a permanent magnet (113) for applying a magnetostatic field to the membrane (115), a flat coil (114) for applying an exciting oscillating field to a part of the membrane (115) and acquiring echo signals corresponding to the exciting oscillating field, and an amount-of-solvent calculating section (124) for calculating the T2 relaxation time constant from the intensities of the echo signals and calculating the amount of protic solvent in a specific region of the membrane (115) from the calculated T2 relaxation time constant. A passage groove through which a fluid containing the protic solvent flows is formed in the permanent magnet (113). The membrane (115) is formed parallel to the passage formation surface of the permanent magnet (113), and the permanent magnet (113) applies a magnetostatic field in the direction of the thickness of the membrane (115).

Description

Specification

Measuring device, fuel cell including the same, and measuring method

TECHNICAL FIELD [0001] The present invention relates to a measuring apparatus, a fuel cell including the same, and a measuring method, and more particularly, to a background art relating to a technique for locally measuring the distribution of the amount of a protic solvent in a membrane

[0002] In a functional material such as a membrane, the amount of solvent in the material may dominate the performance of the material. In the design and development of such materials, it is an important technical issue to measure the solvent distribution locally. Examples of such functional materials include solid polymer electrolyte membranes used in fuel cells.

In a fuel cell including a solid polymer electrolyte membrane, a gas containing water vapor is supplied as a fuel and an oxidant from a flow channel formed in a separator during operation. The supply of fuel and oxidant causes a distribution in the amount of water in the solid polymer electrolyte membrane, and the distribution state changes with time. In order to improve the operation efficiency of such fuel cells, it is important to accurately grasp the wet state of the solid polymer electrolyte membrane and control the supply of fuel and oxidant.

As described above, the case of a fuel cell has been described as an example. If the distribution of the amount of the protonic solvent contained in the membrane can be grasped locally on the spot, it is useful for evaluating the performance of the material.

[0005] Here, as a technique for locally measuring the amount of the protonic solvent at a specific portion of a sample, there is a conventional one described in Patent Document 1. In this document, the Malczech method is applied locally to a specific part of the sample, the relaxation time constant is measured by 1 H-NMR, and the amount of the protonic solvent in the specific part of the sample is measured locally. The technology to do is described. According to this technique, it is possible to measure the amount of local protonic solvent at a specific location in a substance in a relatively short time using the measurement result of NMR.

[0006] Further, as another conventional technique related to NMR measurement of a sample, Patent Document 2 and And those described in 3.

Patent Document 2 describes that NMR measurement of a sample is performed using a U-shaped magnet and a solenoid coil.

Patent Document 3 describes a moisture distribution measuring device for a polymer film. In this method, the MR I image of the polymer membrane is acquired and the moisture distribution is acquired.

[0007] Patent Document 1: International Publication No. 2006/030743 Pamphlet

Patent Document 2: Japanese Patent Application Laid-Open No. 54-1 27785

Patent Document 3: Japanese Patent Application Laid-Open No. 2004_1070297

Non-special text Ι ：： Tsushima Si ^ n 2 ¾ “Magnetic resonance imaging of the wa ter distribution within a polymer electrolyte membrane in fuel eel Is J, ELECTROCHEMICAL AND SOLID-STATE LETTERS, 7 (9), A269-A272, 2004 Non-Patent Document 2: Keigo Takenaka, “Solid Polymer Electrolyte Water Electrolysis Technology and Its Applications”, Soda and Chlorine, Vo, 37, p. 323-337 (1 986)

Disclosure of the invention

[0008] Here, if the distribution of the protonic solvent when the protonic solvent diffuses in the thickness direction and the plane direction in the film from a part of the film surface, the characteristics of the film can be measured. Useful for evaluation. For example, the above-described solid polymer electrolyte membrane of a fuel cell is useful for optimal control of the operating state during battery operation.

[0009] In a solid polymer electrolyte membrane of a fuel cell, water (protonic solvent component) force in a wet gas diffuses into the membrane from a region facing the groove of the separator. The amount of the protonic solvent in the membrane is adjusted by the water supply from the wet gas and the water (protonic solvent component) produced by the reaction of the fuel gas and the oxidant. Within the separator of a fuel cell, there is a distribution in the concentration of fuel gas and oxidant between the inlet and outlet, and the water produced by the membrane (proton properties) also depends on the active state of the catalyst. There is a spatial distribution in the amount of solvent component. Also, even when the amount of protonic solvent in the membrane is adjusted by flowing wet gas around the membrane, there is a difference in the concentration of the protonic solvent at the inlet and outlet of the wet gas. A spatial distribution of the concentration of the protonic solvent also occurs in the road. As a result, the membrane protocol A spatial distribution is formed in the amount of the organic solvent.

[0010] Therefore, the development of a membrane that minimizes the distribution of the amount of protonic solvent in the membrane as much as possible, and the prototon of wet gas supplied so that the fuel cell can be operated with the optimum amount of protonic solvent. It is necessary to control the concentration of the organic solvent.

[001 1] For this purpose, a device for measuring the spatial distribution of the amount of the protonic solvent in the membrane is required. However, the conventional measuring device described above has a protonic solvent from a specific part of the membrane. It was not always suitable for measuring the amount of protonic solvent in the membrane as it diffused into the membrane.

[0012] According to the present invention,

An apparatus for locally measuring the amount of a protic solvent at a specific location in a film using a nuclear magnetic resonance method,

A permanent magnet for applying a static magnetic field to the film;

Applying an oscillating magnetic field for excitation to a part of the film, and obtaining an echo signal corresponding to the oscillating magnetic field for excitation;

From the intensity of the echo signal, a solvent amount calculation unit that calculates the amount of the protonic solvent at a specific location of the membrane;

With

The permanent magnet is provided with a channel groove through which a fluid containing the protonic solvent flows.

A measuring device is provided in which the film is provided in parallel to the flow path forming surface of the permanent magnet.

[0013] Further, according to the present invention,

A film is arranged in parallel to the flow path forming surface of the permanent magnet formed with the flow path groove, and the amount of the protonic solvent at a specific location in the film is locally measured using a nuclear magnetic resonance method. A method,

While flowing a fluid containing the protonic solvent in the flow channel of the permanent magnet, a static magnetic field was applied to the film by the permanent magnet, and the fluid was placed in the static magnetic field. A first step of sequentially applying an excitation oscillating magnetic field a plurality of times using an RF coil to a part of the film, and acquiring a plurality of echo signals corresponding to the excitation oscillating magnetic field;

A second step of determining the amount of the protonic solvent at a specific location of the film from the intensity of the plurality of echo signals;

A measurement method is provided.

In the present invention, since a permanent magnet having a specific shape having a flow path forming surface is used, a static magnetic field is applied to the film, and a proton solvent is flowed into the flow path groove so that the protons in the film. A distribution can be formed in the amount of the organic solvent. Then, by applying an excitation oscillating magnetic field to the part of the film on which the distribution of the amount of the protonic solvent is formed using an RF coil, an echo signal is obtained, thereby distributing the protonic solvent in the film. Can be detected.

In addition, since the film is arranged in parallel to the flow path forming surface of the permanent magnet, it is possible to reliably align the measurement location when performing the measurement using the permanent magnet having a specific shape and the RF coil.

[0015] Therefore, according to the present invention, for example, in a state where the protonic solvent flowing through the flow channel is supplied into the membrane, or conversely, the protonic solvent is discharged from the membrane, The amount of protonic solvent in the membrane can be measured in situ. In addition to applying a static magnetic field to the membrane, supplying a protonic solvent to the channel by supplying a protonic solvent to the membrane, or conversely draining the solvent from the membrane, the membrane can have a desired It can adjust so that it may become a tonality solvent amount. At that time, in order to confirm whether the amount of the protonic solvent in the membrane is spatially uniform or a spatial distribution is formed, an RF coil is used to excite part of the membrane. By applying an oscillating magnetic field, echo signals can be acquired, and the distribution of the amount of protonic solvent can be obtained.

In addition, it is possible to evaluate the diffusion behavior of the protonic solvent in the in-plane direction of the membrane. For example, a simulation device for evaluating the distribution of the protonic solvent in the solid polymer electrolyte membrane of the fuel cell, etc. It is preferably applied to other film evaluation devices be able to. Further, as will be described later, the measuring apparatus of the present invention can be incorporated into a fuel cell, for example.

[001 6] According to the present invention, an echo signal can be obtained by performing measurement while flowing a fluid containing a protonic solvent in the flow channel groove of the permanent magnet. It is not essential in the present invention to flow the fluid in the flow channel, and the measurement may be performed in a state in which no fluid flows. Examples of the protonic solvent include water and alcohols such as methanol and ethanol.

[001 7] Further, in this specification, the “echo signal” may be a signal that corresponds to the excitation oscillating magnetic field and functions as an NMR signal capable of calculating the T ₂ relaxation time constant.

[0018] In the present specification, "static magnetic field" is completely a magnetic field that is stable in time to such an extent that the echo signal and the T ₂ relaxation time constant can be acquired stably. It does not have to be a stable magnetic field, and there may be some variation within that range.

[001 9] In the measuring apparatus of the present invention, the solvent amount calculating section, from the intensity of the echo signal, and calculates the T ₂ relaxation time constant, from the calculated said T ₂ relaxation time constant, specific portions of the film The amount of the protonic solvent in may be calculated.

Further, in the measurement method of the present invention, the second step is from the strong degree of the echo signals, calculating a T ₂ relaxation time constant, the pro tons of solvent content and T ₂ relaxation time constant in the film acquires data indicating the correlation, including from the said data and T ₂ wherein T ₂ relaxation time constant calculated in the step of calculating the relaxation time constant, and determining the amount of the pro ton solvent, the You may go out.

( ₂ ) By calculating the amount of protonic solvent from the relaxation time constant, it is possible to further simplify the calibration of measured values depending on the device configuration.

[0020] Here, in the vicinity of the surface of the permanent magnet, the magnitude of the static magnetic field changes along the normal direction of the surface. In addition, when the flow path is provided on the surface of the permanent magnet, a spatial distribution different from the case where there is no flow path occurs in the magnitude of the static magnetic field in the upper part of the flow path forming surface. The resonance frequency in the measurement of the membrane changes depending on the strength of the static magnetic field at the measurement location, so that the echo signal can be acquired reliably. For this purpose, it is important to reliably adjust the relative position between the permanent magnet and the measurement location of the membrane, and to reliably form an oscillating magnetic field for excitation at the measurement location in the membrane.

[0021] From the viewpoint of more precisely adjusting the distance between the permanent magnet and the film, for example, the flow path groove of the permanent magnet may include a plurality of groove portions arranged in parallel to each other. In this way, even when the measurement target is a flexible film, the projections (flow channel forming surface) formed between the plurality of groove portions are separated from the flow channel forming surface at a specific interval. Can be supported. Therefore, the distance between the film and the flow path forming surface in the ray direction of the flow path forming surface can be maintained in a state of being regulated to a specific size, and the film can be stably held in the vicinity of the flow path forming surface. At this time, one surface of the film may be in direct contact with the flow path forming surface of the permanent magnet, or the distance adjustment made of a nonmagnetic material between the flow path forming surface and the film. A member may be interposed.

[0022] In the present invention, the RF coil may form the excitation oscillating magnetic field having an amplitude in a direction in the flow path forming plane and perpendicular to the extending direction of the groove. . In this way, the magnetostatic field intensity in the plane parallel to the flow path formation surface is uniform in the following areas (i) and (ii) in the upper area of the flow path formation surface. Regions can be formed.

(i) a region sandwiched between adjacent grooves, the region along the direction in which the flow path forming surface extends, and

(i i) An upper region of a single groove part, and an area along the extending direction of the groove part.

[0023] In the above (i), the static magnetic field in the cross section perpendicular to the extending direction of the groove portion is maximized. Therefore, the region (i) is formed by extending the groove portion in a plane parallel to the flow path forming surface. This is a region where the change in the direction of the static magnetic field is small. In (ii) above, since the static magnetic field in the cross section perpendicular to the extending direction of the groove is minimized, the region (ii) is defined by the extending direction of the groove in the plane parallel to the flow path forming surface. This is the region where the change of the static magnetic field is small.

[0024] Therefore, by using the above (i) or (ii) as the measurement region, the local amount of the protonic solvent can be measured with higher accuracy. Also, magnetostatic Forming multiple regions with uniform field strength is even more suitable from the viewpoint of accurately performing multipoint measurement.

[0025] When (i) or (ii) is used as a measurement region, for example, the RF coil includes a pair of coil portions, and the excitation is performed in a region sandwiched between the pair of coil portions. Forming an oscillating magnetic field, and when viewed from above the flow path forming surface of the permanent magnet, a region sandwiched between the pair of coil portions is in or adjacent to the formation region of the single groove portion It can be configured to be included in a region sandwiched between the groove portions.

[0026] Of these, when (i) is the measurement region, the flow path forming surface of the permanent magnet, R

From the viewpoint of further reliably suppressing the positional deviation of the F coil and the film, the RF coil is a plane in which the first coil portion including the first linear region and the second coil portion including the second linear region are connected. The first coil portion and the second coil portion are conductive coils, and the first linear region and the second linear region are parallel to the extending direction of the groove portion. The region sandwiched between the first straight region and the second straight region when viewed from above the flow path forming surface of the permanent magnet is located within the region sandwiched between the adjacent groove portions. It may be a configuration included in

[0027] By arranging the linear region of the RF coil on the upper part of the flow path forming surface of the permanent magnet, the region where the static magnetic field strength is uniform in the plane parallel to the flow channel groove forming surface is defined as the measurement region. can do. In addition, since the straight region can be directly or indirectly supported by the flow path forming surface by arranging the straight region above the flow path forming surface, the gap between the flow path forming surface and the straight region can be reduced. This further suppresses the measurement of the amount of protonic solvent with higher accuracy.

[0028] Also, when the above (ii) is used as a measurement region, the RF coil is a planar coil in which a first coil portion including a first linear region and a first nicole portion including a second linear region are connected. The first coil portion and the second coil portion have a conductive wire reversely wound, and the first linear region and the second linear region are arranged in parallel to the extending direction of the groove portion, and the permanent magnet As viewed from the top of the flow path forming surface In some cases, a region sandwiched between the first straight region and the second straight region may be included in a single groove forming region.

[0029] In the upper region of the groove, as will be described later with reference to Fig. 3 (b), the static magnetic field strength becomes maximum at a specific distance from the flow path formation surface in the normal direction of the flow path formation surface. The By setting the region where the static magnetic field intensity is maximized as the measurement region, the fluctuation of the static magnetic field during measurement can be further suppressed, and thus the amount of the protonic solvent can be measured more accurately.

[0030] Further, from the viewpoint of more reliably suppressing the displacement of the flow path forming surface of the permanent magnet, the RF coil, and the film, the RF coil is provided between the flow path forming surface of the permanent magnet and the film. A gap having a specific thickness formed by a nonmagnetic material between the flow path forming surface of the permanent magnet and the planar coil, and between the planar coil and the film. An adjustment member may be arranged.

[0031] According to the present invention, there is provided a fuel cell comprising the above-described measuring device of the present invention. This fuel cell may include, for example, a solid polymer electrolyte membrane as a membrane. At this time, since the local amount of the protonic solvent in the solid polymer electrolyte membrane can be measured, the distribution of the protonic solvent in the solid polymer electrolyte membrane can be directly obtained.

[0032] In particular, in the measuring apparatus of the present invention, since the flow channel is provided on the surface facing the permanent magnet film, for example, a separator provided facing the fuel electrode or oxidant electrode of the fuel cell. At least a part of this can be constituted by a permanent magnet of the measuring device. This simplifies the overall configuration of the fuel cell, while supplying fuel or an oxidant, and even water vapor to the fuel cell electrode, and the amount of local protonic solvent in the polymer electrolyte membrane. Can be measured.

[0033] In this configuration, the flow path forming surface of the permanent magnet is disposed opposite to the fuel electrode of the fuel cell, and a fuel gas may be supplied to the flow path groove. The flow path forming surface of the fuel cell may be disposed opposite to the oxidant electrode of the fuel cell, and an oxidant gas may be supplied to the flow path groove.

[0034] As described above, according to the present invention, a specific shape permanent having a flow path forming surface is provided. To apply a static magnetic field to the film with a magnet and apply an oscillating magnetic field for excitation to a part of the film placed in the static magnetic field, and to obtain a plurality of echo signals corresponding to this, A distribution can be formed in the amount of the protonic solvent in the film, and the distribution state can be accurately detected.

In addition, by flowing a fluid containing fuel or oxidant and a protonic solvent in the flow channel, the amount of protonic solvent in the membrane is adjusted, and multiple echo signals corresponding to this are obtained. It is possible to accurately detect the spatial distribution of the amount of protonic solvent in the membrane.

As a result, it is possible to measure the local amount of the protonic solvent in the film on the spot while flowing a fluid containing the protonic solvent in the channel groove of the permanent magnet.

It is also possible to evaluate the diffusion characteristics of the amount of protonic solvent in the plane direction of the membrane.

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of a permanent magnet in an embodiment.

FIG. 2 is a diagram showing a configuration of a permanent magnet in the embodiment.

FIG. 3 is a diagram for explaining the measurement result of the z position distribution of the static magnetic field strength formed by the permanent magnet in the embodiment.

FIG. 4 is a diagram for explaining the measurement result of the y-position distribution of the static magnetic field strength formed by the permanent magnet in the embodiment.

FIG. 5 is a diagram for explaining the measurement result of the X position distribution of the static magnetic field strength formed by the permanent magnet in the embodiment.

FIG. 6 is a perspective view for explaining a static magnetic field formed by a permanent magnet in the embodiment.

FIG. 7 is a cross-sectional view showing the configuration of the fuel cell in the embodiment.

FIG. 8 is a diagram showing a configuration of a planar coil in the embodiment.

FIG. 9 is a diagram showing a configuration of a measuring apparatus in the embodiment.

FIG. 10 is a cross-sectional view showing the arrangement of permanent magnets, a flat coil, and a sample of the measuring apparatus according to the embodiment. FIG. 11 is a diagram showing a configuration of a measuring apparatus in the embodiment.

FIG. 12 is a diagram showing a measurement result of an echo signal in an example.

FIG. 13 is a diagram showing the relationship between the distance between the coil and the sample and the echo signal intensity in the example.

FIG. 14 is a diagram showing a measurement result of an echo signal in an example.

FIG. 15 is a graph showing the relationship between the water content of a sample and T ₂ in an example.

FIG. 16 is a graph showing the relationship between the moisture content of the sample and the echo signal intensity in the example.

FIG. 17 is a diagram showing a measurement result of an echo signal in an example.

FIG. 18 is a diagram showing a configuration of a Doub I e-D type coil in an example.

FIG. 19 is a diagram showing a configuration of a Doub I e-D type coil in an example.

FIG. 20 is a diagram for explaining a magnetic field analysis method in an example.

FIG. 21 is a diagram showing magnetic field analysis conditions in the example.

FIG. 22 is a diagram showing the ζ position distribution of the magnetic field strength in the χ direction of the Doub I e-D type coil in the example.

FIG. 23 is a diagram showing contour lines of a magnetic field formed by a Doub I e-D type coil in an example.

FIG. 24 is a diagram showing the ζ position distribution of the χ direction magnetic field strength of the Doub I e-D type coil in the example.

FIG. 25 is a diagram showing magnetic field analysis conditions in the example.

FIG. 26 is a diagram showing contour lines of a magnetic field formed by a Doub I e-D type coil in an example.

FIG. 27 is a diagram showing a ζ position distribution of χ direction magnetic field strength of a Doub I e-D type coil in an example.

FIG. 28 is a diagram showing an X-direction magnetic field strength distribution ΗX of a Double-D type coil in an example.

FIG. 29 is a diagram showing a ζ position distribution of χ direction magnetic field strength of a Doub I eD type coil in an example. FIG. 30 is a diagram showing a ζ position distribution of χ direction magnetic field strength of a Doub I eD type coil in an example.

FIG. 31 is a diagram showing an echo signal reception intensity distribution of a Doublé-D coil in an example.

FIG. 32 is a diagram showing a z-position distribution of echo signal reception intensity of a Doub I e-D type coil in an example.

FIG. 33 is a diagram showing an echo signal reception intensity distribution of the Doub I e-D type coil in the example.

FIG. 34 is a diagram showing a z-position distribution of echo signal reception intensity of the Doub I e-D type coil in the example.

FIG. 35 is a diagram showing a z-position distribution of echo signal reception intensity of a Doub I e-D type coil in an example.

FIG. 36 is a diagram showing a configuration of a fuel cell in an embodiment.

FIG. 37 is a diagram showing a cell configuration of a fuel cell in an embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In the following embodiment, the amount of the protonic solvent in the film is calculated using a nuclear magnetic resonance (NMR) method.

In the NMR method, the number density and relaxation time constant can be obtained by detecting the motion of nuclear magnetization as an NMR signal due to the spin resonance phenomenon of a nucleus placed in a magnetic field. Examples of the physical quantity corresponding to the atomic number density include the water content in the polymer electrolyte membrane. As the relaxation time constant, for example, there are T T ₂ relaxation time constant, the use of the CPMG method, strongly dependent on the T ₂ (CPMG) relaxation time constant on the water content is obtained. In the following, the CPMG method is used as an example to explain the case where the excitation vibration magnetic field is applied as a high-frequency pulse sequence.

[0038] In addition, the measuring apparatus of the present invention includes a permanent magnet having a specific shape having a flow channel and an RF detection coil (also simply referred to as "RF coil") that applies an excitation oscillating magnetic field. Prepare. Therefore, in the following, first, specific examples of the permanent magnet and the RF coil constituting the measuring apparatus in the first embodiment and the second embodiment will be shown. In the third embodiment, a specific configuration of a measuring apparatus in which the permanent magnet and the RF coil are combined will be described. Furthermore, in the fourth embodiment, a specific example of a fuel cell including the measuring device described in the third embodiment is shown.

[0039] (First embodiment)

In the present embodiment, the configuration of the permanent magnet used in the third embodiment will be described. FIG. 1A and FIG. 1B are diagrams showing the configuration of the permanent magnet of the present embodiment. Fig. 1 (b) is a partial cross-sectional view of Α_Α 'in Fig. 1 (a).

1 (a) and 1 (b) show an example of the shape and dimensions of the permanent magnet 1 1 3; however, the shape and dimensions of the permanent magnet 1 1 3 are not limited to those shown in the figure. . The unit of the dimension attached to the double-sided arrow in Fig. 1 (b) is mm. FIG. 2 is a view showing a permanent magnet manufactured with the dimensions shown in FIG.

The permanent magnet shown in FIGS. 1 and 2 is a member made of a magnetic material and applying a static magnetic field to a film to be measured in a protonic solvent amount measuring apparatus. Examples of the material of the permanent magnet 1 1 3 include neodymium, iron, and boron materials such as NEOMAX (registered trademark) manufactured by NEOMAX.

[0041] In FIGS. 1 (a) and 1 (b), the permanent magnet 1 1 3 force is exemplified by a configuration in which blocks made of a plurality of magnetic materials are joined, but the permanent magnet 1 1 3 is a single unit. The structure which consists of these blocks and does not have a junction part may be sufficient.

The permanent magnet 1 13 is provided with a flow path forming surface, and the flow path forming surface is provided with a flow path groove 110 1 through which a fluid containing a protonic solvent flows. The film to be measured is provided in parallel to the flow path forming surface of the permanent magnet 1 1 3. The permanent magnets 1 1 3 apply the static magnetic field in the normal direction of the film.

In the following description, the flow path forming surface of the permanent magnet 1 13 corresponds to the top surface of the convex part 103, and the groove part included in the flow path groove 101 corresponds to the concave part 105.

The flow path forming surface of the permanent magnet 1 1 3 has a plurality of recesses 1 provided alternately in succession. Including an uneven surface constituted by 0 5 and convex portions 1 0 3. The plurality of convex portions 10 3 and the plurality of concave portions 10 5 all extend in parallel with each other. Both the convex portion 103 and the concave portion 105 extend linearly in one specific direction (the X direction in the figure).

Further, the top surfaces of the plurality of convex portions 10 3 are all located in the same plane, and the bottom surfaces of the plurality of concave portions 1 0 5 are all parallel to the top surface of the convex portion 10 3. Located in the same plane. In FIG. 1 (a), the case where the top surface of the convex portion 103 and the bottom surface of the concave portion 105 are both horizontal to the xy plane is illustrated.

In the AA ′ cross section, the width of the plurality of convex portions 103 (y direction) and the width of the plurality of concave portions 105 are both substantially equal.

The permanent magnet 1 1 3 used in the present embodiment has a groove on the opposite side (lower surface side in FIG. 1 (a)) to the formation surface (the upper surface in FIG. 1 (a)) of the projections 1 0 3 and 1 5 5. 1 0 5 a is formed. The groove portion 10 5 a is formed by digging in a direction intersecting with the extending direction of the recess portion 10 5 (y direction in the figure). Further, the groove portion 10 5 a is formed deepest at the center in the extending direction of the recessed portion 10 (X direction in the figure) and shallowest at both end sides. The specific transverse plane of the groove portion 10 5 a (cross section cut perpendicular to the y-axis in the figure) The shape is not particularly limited, but in the present embodiment, this is a triangle. In addition, the cross-sectional shape of the groove portion 10 5 a may be a semicircular shape or a parabolic shape.

When the permanent magnet 1 1 3 having such a configuration is arranged in the space, it is in the plane parallel to the flow path forming surface (the xy plane in the figure) on the upper part of the convex part 10 3 and the upper part of the concave part 1 5. A region having a uniform static magnetic field strength is formed.

Among these, in the upper part of the convex portion 103, a region having a uniform static magnetic field strength in a plane parallel to the flow path forming surface is formed along the extending direction of the convex portion 103. Along with the width of the convex portion 103, it is formed over a specific width.

In addition, in the upper part of the concave portion 105, a region having a uniform static magnetic field strength in a plane parallel to the flow path forming surface is formed along the extending direction of the concave portion 105, and the concave portion It is formed over a specific width in the width direction of 105. These areas can be used as measurement areas when performing local NMR measurement of the film.

[0046] Hereinafter, it will be described more specifically that a uniform static magnetic field plane is formed in the upper part of the convex portion 103 and the concave portion 105 along the extending direction.

The inventor evaluated the spatial distribution of the static magnetic field strength using the permanent magnet shown in FIG. A Gauss meter (TM-501 manufactured by KAN ET EC) was used as a measuring device. For the static magnetic field strength, only the z-direction component was measured. Figures 3, 4 and 5 show the measured static magnetic field strength (z-direction component) in the z-axis direction (normal direction of the flow path forming surface), y-axis direction (cross-sectional direction of the groove), and X The distribution of the position in the axial direction (extending direction of the groove) was shown. Here, the center of the central row of the five convex parts of the permanent magnet shown in Fig. 2 is set to y = Omm.

[0047] FIGS. 3 (a) and 3 (b) are diagrams illustrating the measurement results of the position distribution of the static magnetic field strength H _Q (z-direction component) in the z-axis direction. 4 (a) and 4 (b) are diagrams illustrating the measurement results of the position distribution in the y-axis direction of the static magnetic field strength H _Q (z-direction component).

[0048] From Fig. 3 (b) and Fig. 4 (b), in the upper region of the convex part 103 (y = Omm), the magnetic field strength is strongest on the magnet surface ( _Z = Omm), and the magnetic field is far away from the magnet. In other words, it can be seen that the magnetic field strength decreases as z increases. On the other hand, in the upper region of the concave portion 10 05 (y = 6.35 mm), the magnetic field strength becomes maximum at z = 5 to 6 mm, and after that, the magnetic field strength decreases as the distance from the magnet increases.

In addition, in the measurement using the permanent magnet 1 1 3, in terms of suppressing a sudden change in the magnetic field strength in the z direction, the height of the concave portion 1 05 is higher than the height of the concave portion 1 05 on the flow path forming surface. The measurement area can be a position of 1/4 or more of the depth of 05, preferably a position of 1/3 or more. The upper limit of the height of the measurement area is not particularly limited. For example, from Fig. 3 (b), the static magnetic field in the z direction is rapidly increased up to about 1.5 times the depth of the recess 105. Fluctuations can be suppressed.

[0050] From FIG. 3 (b), in the upper part of the recess 105, the area where the magnetic field strength becomes maximum is obtained. A zone is formed. The region where the magnetic field intensity is maximum is not formed on the plane of the permanent magnet having no flow channel 10 1, but is a phenomenon unique to the permanent magnet 1 1 3 having the flow channel 1 0 1. . In the vicinity of the region where the magnetic field strength at the top of the recess 105 is maximum, for example, in the region of the height of 1/3 or more and 3/2 or less of the depth of the recess 105, it is horizontal to the flow path formation surface. Since the amount of change in the static magnetic field strength in the in-plane direction is even smaller, changes in the measured value due to the displacement of the measurement position can be further suppressed when performing NMR measurement of the film.

[0051] From FIG. 3 (b), the magnetic field strength is about 0.2 to 0.3 Tes Ia even at a position away from the magnet, for example, z> 1 Omm. As shown in the examples described later, NMR measurement is sufficiently possible with such a magnetic field strength.

[0052] From Fig. 4 (b), regardless of the position of z, at the position of the central axis (y = 0 mm) of the convex part 103 and the central axis (y = 6.35mm) of the concave part 105, The magnetic field strength has a maximum value and a minimum value, respectively. In the vicinity of these two y positions, the magnetic field is flat, and in this embodiment, this region is a position where NMR measurement is performed.

[0053] FIGS. 5 (a) to 5 (c) are diagrams for explaining the measurement results of the position distribution in the x-axis direction of the static magnetic field strength _HQ (z-direction component). Fig. 5 (a) shows a cross section of the permanent magnet 1 13 with respect to the extending direction of the convex portion 103 and the concave portion 105. Fig. 5 (b) shows the extending direction of the convex portion 103 and the concave portion 105. A cross section of a permanent magnet 1 1 3 perpendicular to is shown.

[0054] Fig. 5 (c) is a diagram showing the position distribution in the X-axis direction of the static magnetic field strength _HQ (z-direction component). In other words, Fig. 5 (c) shows the magnetic field strength in the groove direction. From FIG. 5 (c), it can be seen that the magnetic field strength is almost uniform along the extending direction of both the upper part of the convex part 103 and the upper part of the concave part 105. This is because, as described above, the groove 1 05 a is dug and formed on the surface opposite to the formation surface of the convex portion 103 and the concave portion 105, and the thickness of the permanent magnet 1 13 is set in the X direction (extension of the concave portion 105. Direction) due to being thin at the center and thick at both ends.

In this way, the static magnetic field strength H ₀ was made uniform in the extending direction of the recess 105. Thus, the nuclear magnetic resonance frequency of the film at the time of NMR measurement becomes uniform in the extending direction of the groove, that is, in the extending direction of the convex portion 103 and the concave portion 105.

[0055] From the above results, for example, by arranging the film and the RF coil so that the first region 10 07 and the second region 10 09 shown in FIG. The static magnetic field strength can be selected as appropriate, and the spatial distribution of the static magnetic field can also be selected as appropriate, so that the nuclear magnetic resonance frequency and measurement region to be measured can be adjusted, and NMR measurement can be performed with even higher accuracy according to the device and measurement sample. It becomes.

FIG. 6 is a perspective view showing the first region 1 07 and the second region 1 0 9 which are NMR measurement smooth with the permanent magnet 1 13 of the present embodiment. In FIG. 6, the first region 10 07 is a region above the convex portion 10 3 near y = 0 mm, and the first region 10 07 is formed along the extending direction of the convex portion 103. Has been. The second region 109 is a region above the recess 105 near y = 6.35 mm, and is formed along the extending direction of the recess 105.

As shown in FIG. 6, when viewed from the upper part of the flow path forming surface of the permanent magnet 1 1 3, a region where the static magnetic field strength is uniform in a plane parallel to the flow path forming surface (first The region 10 7 and the second region 10 9) are formed as cylindrical regions on the upper part of the convex part 103 and the upper part of the concave part 105, respectively.

[0058] In the cross-sectional view in the extending direction of the recess 1005, the width of the first region 1007 and the second region 1009 is the position in the z direction as shown in Fig. 4 (b). For example, for the first region 1 07, for the region of about 1/4 of the width of the protrusion 1 0 3 on both sides from the center (maximum point) of the protrusion 1 0 3, It can be a region where the spatial non-uniformity of the static magnetic field is small. For the second region 1 0 9, the spatial nonuniformity of the static magnetic field is about 1/4 of the width of the recess 1 0 5 on both sides from the center (minimum point) of the recess 1 0 5. It can be a small area.

In addition, the permanent magnet 1 1 3 of this embodiment has a shape with an uneven surface, and the NMR measurement is performed with the uneven surface facing the film in parallel. For this reason, for example, the permanent magnet 1 1 3 can be incorporated into the fuel cell as a separator (gas flow path). Is possible. By using the permanent magnet 113 as a separator for the fuel cell, it is possible to measure the amount of the protonic solvent in the electrolyte layer of the fuel cell such as a solid polymer electrolyte membrane. A configuration example of a fuel cell provided with a measuring device having permanent magnets 11 and 13 will be described in more detail in the fourth embodiment.

In the present embodiment, a configuration in which a plurality of recesses 10 5 (grooves) are independently provided on the flow path forming surface of the permanent magnet 1 13 is illustrated. The shape of 1 is not limited as long as a plurality of protrusions 103 and recesses 105 are repeatedly provided in a cross-sectional view, and in a plan view, a plurality of groove portions communicate with each other. There may be. Even in the case where a plurality of grooves are connected, if the permanent magnet has the cross-sectional shape described above with reference to FIGS. 3 to 6, the static magnetic field distribution according to the static magnetic field distribution shown in FIGS. Since it is formed, it can be used as a permanent magnet used to measure the distribution of the amount of protonic solvent in the film.

In the present embodiment, the configuration in which the plurality of flow portions included in the flow channel groove extend in parallel to each other is illustrated, but the planar shape and the planar arrangement of the flow channel are not limited thereto.

[0061] (Second Embodiment)

In the present embodiment, the configuration of the RF coil used in the measurement apparatus of the third embodiment will be described. In the following description, the case where the membrane to be measured is a solid polymer electrolyte membrane will be described as an example.

As described above with reference to FIG. 6 in the first embodiment, in the permanent magnet 11 3 used in the measuring apparatus for the amount of the protic solvent, the top surface of the convex portion 103 and the concave portion 1 0 5 A static magnetic field H _Q is formed in a direction perpendicular to the bottom surface (z direction, upward in the figure). In addition, in the regions above the convex portions 103 and the concave portions 105, the NMR measurement is further facilitated along the extending directions, and regions are formed.

Therefore, in the present embodiment, a planar coil configured to form an oscillating magnetic field for excitation in the first region 10 7 or the second region 1 09 is used as the RF coil. Hereinafter, when the planar coil forms an oscillating magnetic field for excitation in a direction perpendicular to the static magnetic field, specifically, it hangs in the direction in which the flow path is formed and in the direction in which the groove extends. A case where an excitation oscillating magnetic field having an amplitude in a straight direction is formed will be described as an example.

FIG. 8 is a diagram schematically showing the configuration of the planar coil. The number and shape of the planar coil are not limited to this. The planar coil 1 1 4 shown in FIG. 8 includes a pair of coil portions (first coil portion 1 1 9, second coil portion 1 2 1) and is excited in a region sandwiched between the pair of coil portions. Form an oscillating magnetic field. In addition, the planar coil 1 1 4 is, for example, a region sandwiched between a pair of coil portions when viewed from the upper part of the flow path forming surface of the permanent magnet 1 1 3, within a single groove portion forming region. Or it is used by arrangement | positioning included in the area | region pinched | interposed into the adjacent groove part.

In FIG. 8, the first coil portion 1 1 9 force is a coil portion including the first linear region 1 23 and the conductive wire is wound in the right-handed direction. The second coil portion 1 2 1 force is the second linear region 1 Although an example is shown in which the conductive wire is coiled in a left-handed winding including 25, the winding method of the conductive wire in each coil portion is not limited to this. If current flows in the same direction in the first linear region 123 and the second linear region 125, an excitation oscillating magnetic field perpendicular to the linear region and parallel to the coil surface is formed between these linear regions.

[0066] More specifically, the planar coil 1 1 4 is of the Doub Ie_D type (also called an 8-shaped coil or a butterfly coil). Doub I e _D type coil has a shape in which a conducting wire is wound in a semicircular shape and two coils face each other, and the two semicircular strings correspond to the straight part, and the strings are arranged parallel to each other Is done.

FIG. 8 shows specific dimensions of the planar coil 114 and the LC resonance circuit. As an example of the dimensions of the planar coil 1 14, a 0.2 mm diameter copper wire is wound in 5 semi-circles each having a diameter of 12 mm, and the strings are arranged in parallel at intervals of 1.2 mm. In Fig. 8, for simplicity, three copper wires are shown schematically. The resonance frequency of this coil is, for example, 13.07 MHz. The Q value of the chlority factor of the manufactured coil is 25. However, the dimensions and number of turns of the illustrated planar coil 1 14 are examples designed according to the dimensions of the permanent magnet 1 1 3 shown in FIG. 1, and are not limited to these dimensions.

[0068] It has two linear regions parallel to each other like a Do ub I e_D type coil In the planar coil 1 1 4 with a combination of coil parts, the area between the first linear area 1 2 3 and the second linear area 1 2 5, that is, around the symmetrical axis of the two semicircular coils An oscillating magnetic field is formed in As shown in the analysis results of the examples described later, the periphery of this symmetry axis is the detection region (measurement region) of the planar coil 1 14. Therefore, if the two first regions 1 0 7 or the second region 1 0 9 of the permanent magnet 1 1 3 shown in FIG. 6 are superimposed on the detection region of the planar coil 1 14, the static magnetic field H ₀ And the oscillating magnetic field H are perpendicular to each other, the region near the symmetry axis of the pair of coil parts is a more preferable region for NMR measurement.

Note that the spatial distribution of the oscillating magnetic field formed by the planar coils 1 1 and 4 will be described in more detail in the examples described later.

[0069] By using the planar coil 1 1 4 of this embodiment in combination with the first embodiment, a region where the static magnetic field is uniform in the plane (first region 1 0 7, second region 1 0 9 ), And an oscillating magnetic field for excitation can be reliably formed in these regions. Then, a film is arranged on the upper part of the first area 10 07 or the second area 10 09, and the first signal 10 07 or the upper area of the second area 10 09 is used as a measurement area to output an eco signal. Acquiring can improve the accuracy of NMR measurement of the film.

In particular, in the permanent magnet 1 1 3 used in the present embodiment, the groove 1 0 5 a is dug on the opposite surface (lower surface) side of the formation surface (upper surface) of the protrusion 1 0 3 and the recess 1 0 5 as described above. By forming and adjusting the thickness of the permanent magnet 1 1 3, the static magnetic field strength in the extending direction (X direction) of the recess 1 0 5 is made uniform (see Fig. 1 (a) and Fig. 5 (c)). See). As a result, the static magnetic field strength is made uniform throughout the detection region of the planar coil 114, and the resonance frequency of the proton in the sample becomes a more uniform frequency throughout the detection region. Therefore, the NMR signal, which is the sum of the vectors, increases, and the SN ratio can be improved.

[0070] In addition, since a plurality of planar coils such as the planar coil 1 14 need not be stacked, the structure is suitable for multipoint measurement in the thickness direction of the film. When viewed from the top of the flow path forming surface of the permanent magnet 1 1 3, multiple planar coils 1 1 4 are stacked The distribution of the amount of protonic solvent in the thickness direction at a specific location in the plane of the membrane can be measured. It is also possible to perform measurement at different positions in the thickness direction of the film by using one planar coil 1 14. The resonance frequency in NMR measurement changes depending on the strength of the static magnetic field. With this magnet, the magnetic field strength changes in the direction of the film thickness, and the resonance frequency changes accordingly. NMR measurement can be performed by selecting the measurement position in the thickness direction of the film according to the difference in frequency. This difference in resonance frequency can also suppress the interference of NMR signals.

[0071] Further, if a plurality of planar coils 1 1 4 are arranged in the first region 1 0 7 or the second region 1 0 9, multipoint measurement can be performed in the same static magnetic field. This configuration is also suitable for measuring the distribution in the in-plane direction, and for measuring the amount of the protonic solvent multiple times in the region where the film faces a specific recess 105. In addition, since the magnitude of the static magnetic field in the plane parallel to the flow path forming surface differs between the upper part of the convex part 10 3 and the upper part of the concave part 1 0 5, a planar coil 1 1 4 is arranged in each of these. Then, signal interference can be more effectively suppressed.

[0072] Also, as will be described later in the fourth embodiment, when the permanent magnet 1 1 3 is used as a separator of a fuel cell, a polymer electrolyte membrane and a separator (the gas diffusion layer is on the separator side) It is desirable to sandwich an RF detection coil between them.

[0073] In this respect, a cylindrical shape such as a solenoid type coil has a three-dimensional shape and cannot be sandwiched in the gap.

On the other hand, if the RF detection coil is planar (sheet-like), it can be easily inserted into the gap. In the present embodiment, by using the planar coil 1 1 4 as the RF coil, even when the solid polymer electrolyte membrane is measured using the permanent magnet 1 1 3 as the separator of the fuel cell, It is easy to incorporate, and the overall size of the fuel cell can be suppressed.

[0074] In the above, the case where the planar coil 1 1 4 is a Doub I e _ D type coil having two half-moon-shaped coil portions is illustrated, but the planar coil 1 1 4 is First coil part 1 1 9 and second straight line with first straight region 1 2 3 The second coil portion 1 2 1 including the region 1 2 5 is included, and the conductive wire of these coil portions may be configured to be reversely wound, and the planar shape of the coil portion is not limited to the half-moon shape. For example, the planar shape of the two coil portions may be a polygon such as a square, a rectangle, or a triangle.

In addition, the planar coil 1 14 is not particularly limited in size as long as it is configured to apply an excitation oscillating magnetic field to a part of the film, but can be made smaller than the film to be measured, for example. . Further, the planar coil 1 1 4 can be made smaller than the flow path forming surface of the permanent magnet 1 1 3, for example. More specifically, in the cross-sectional view of the extending direction of the groove portion of the permanent magnet 1 1 3, the width of the planar coil 1 1 4 is set to the convex portion 10 3 and the concave portion 1 0 5 of the permanent magnet 1 1 3, respectively. It may be larger than the sum of the width of each piece. Further, the width of the planar coil 1 1 4 may be smaller than the sum of the widths of the concave portion 1 0 5 and the convex portion 1 0 3, or may be made smaller than the width of one convex portion 1 0 3. May be. In this way, when the planar coil 1 1 4 is placed between the flow path forming surface of the permanent magnet 1 1 3 and the film, the z direction between the planar coil 1 1 4 and the permanent magnet 1 1 3 and the film It is possible to more reliably regulate the interval.

[0076] (Third embodiment)

The present embodiment relates to a measuring apparatus including the permanent magnet 1 1 3 described in the first embodiment and the RF coil (planar coil 1 1 4) described in the second embodiment.

FIG. 9 is a diagram showing a configuration of the measurement apparatus of the present embodiment. The measuring device 100 shown in FIG. 9 is a device that locally measures the amount of the protonic solvent at a specific location in the film using the nuclear magnetic resonance method. Hereinafter, the case where the proton solvent is water will be described as an example.

[0078] Measuring device 1 0 0

Permanent magnet that applies a static magnetic field in a specific direction to the film 1 1 5 to be measured 1 1 3 A vibrating magnetic field for excitation is applied in a direction perpendicular to the static magnetic field to the film 1 1 5 To obtain an echo signal corresponding to the oscillating magnetic field for excitation, a planar coil 1 1 4, and

From the intensity of the echo signal, calculates a the T ₂ relaxation time constant, from the calculated said the T ₂ relaxation time constant, the solvent amount calculation unit that calculates a pro ton solvent amount in a particular portion of the film 1 1 5 (solvent weight Calculation unit 1 2 4)

Is provided.

[0079] As described above in the first embodiment, the permanent magnet 1 1 3 is made of a magnetic material. The film 1 1 5 is disposed in parallel to the flow path forming surface of the permanent magnet 1 1 3. The permanent magnet 1 1 3 applies a static magnetic field in the thickness direction of the film 1 1 5. With this static magnetic field applied, a high frequency pulse for excitation is applied to the film 1 15 and the T ₂ relaxation time constant is measured.

[0080] The planar coil 1 1 4 applies an excitation high-frequency pulse. Planar coil 1

More specifically, 14 is the Doub Ie_D type RF detection coil described in the second embodiment. In addition, in FIG. 9, the arrangement of the force planar coil 1 1 4 in the example in which the two linear regions of the planar coil 1 1 4 are arranged on the upper part of the recess 1 0 5 is not limited to this. You may arrange | position in the upper part of the part 103.

FIG. 10 is a cross-sectional view showing the arrangement of the permanent magnet 1 1 3, the planar coil 1 1 4, and the film 1 1 5 in more detail in the measuring apparatus 1 100 shown in FIG. The In FIG. 10, the case where the membrane 1 15 is a solid polymer electrolyte membrane 1 1 7 is illustrated.

The planar coil 1 1 4 is disposed above the flow path forming surface of the permanent magnet 1 1 3. For example, the flow path forming surface (uneven surface) of the permanent magnet 1 1 3 and the solid polymer electrolyte membrane 1 Arranged between 1 and 7.

Further, as shown in FIG. 10, in the measuring device 100, the permanent magnet 1 1 3 has a convex portion 1 0 3 and a planar coil 1 1 4, and the planar coil 1 1 4 and a solid An interval adjusting member (first spacer 1 2 7, second spacer 1 2 9) with a specific thickness made of a non-magnetic material is placed between the polymer electrolyte membrane 1 1 7 Has been. Permanent magnet 1 1 3 static magnetic field H o direction and Doub I e _ D type The direction of the oscillating magnetic field created by the coil (planar coil 1 1 4) is perpendicular

[0083] In the Doub Ie_D type RF detection coil, the echo signal intensity changes when the distance in the z direction from the solid polymer electrolyte membrane 1 17 is changed. This is because the intensity distribution of the oscillating magnetic field H and the reception sensitivity of the coil change depending on the distance. For example, according to the study by the present inventor, as will be described later in the embodiment, in the Doub I e _D type coil shown in FIG. 8, the maximum echo signal intensity is obtained when the distance is about 1 mm. is there. By experimentally acquiring the intensity distribution of the oscillating magnetic field in advance, the positions of the Doub I e _ D type detection coil and the solid polymer electrolyte membrane 1 1 7 are determined as shown in Fig. 10. be able to.

[0084] As shown in FIG. 10, in the measuring apparatus 100, the first spacer 1 having a specific thickness between the permanent magnet 1 1 3 and the planar coil 1 1 4 is used. By placing 27, keep them at specific intervals. Further, by arranging a second spacer 1 29 between the planar coil 1 14 and the solid polymer electrolyte membrane 1 17, these are maintained at a specific interval. By using these spacers to adjust the relative position (z direction) of the uneven surface of the permanent magnet 1 1 3, the planar coil 1 1 4 installation surface and the solid polymer electrolyte membrane 1 1 7, the solid polymer By precisely adjusting the measurement position in the thickness direction of the electrolyte membrane 1 17, the reception sensitivity of the echo signal can be improved in the measurement region. Therefore, local T ₂ measurement of the solid polymer electrolyte membrane 117 can be performed with high sensitivity and high accuracy.

[0085] Further, from the viewpoint of more reliably suppressing the bending of the solid polymer electrolyte membrane 1 17, the third spacer is formed on the upper portion of the convex portion 103 where the planar coil 11 14 is not disposed. 1 3 5 and a bead-like spacing adjusting member (not shown) in the gap 1 3 7 formed between the third spacer 1 3 5 and the solid polymer electrolyte membrane 1 1 7 May be filled. In this way, the distance between the permanent magnet 1 1 3 and the solid polymer electrolyte membrane 1 1 7 can be adjusted more precisely, and the solid polymer electrolyte membrane 1 1 7 can be held in that state. At this time, the thickness of the third spacer 1 3 5 is the same as the thickness of the first spacer 1 2 7, the second spacer 1 2 9 and the planar coil 1 1 4. More specifically, the thickness is set to be approximately equal to the total thickness of the first spacer 1 27 and the second spacer 1 29.

[0086] In addition, the arrangement shown in FIG. 10 is, for example, a solid polymer electrolyte membrane (PEM) for a fuel cell is held by a separator (permanent magnet 1 1 3), and Doub I 6_0 type in the gap between the two. “Because it can be easily applied to a mode in which a detection coil (planar coil 1 14) is installed, the measuring device 100 is also suitably used for local moisture measurement of a solid polymer electrolyte membrane of a fuel cell. As described above, the measuring apparatus 100 of the present embodiment can be used as an apparatus for evaluating the local water content of a membrane such as a solid polymer electrolyte membrane.

Note that the results of NMR measurement of various samples in the arrangement shown in FIG. 10 and the calculated T ₂ (CPMG) value will be described later in Examples.

Returning to FIG. 9, the configuration of the measuring apparatus 100 will be further described.

The planar coil 1 1 4 may be singular or plural. If the number is plural, it is possible to measure the moisture content distribution in the membrane 1 1 5. In this case, if it is arranged two-dimensionally along the surface of the membrane 115, the two-dimensional moisture content distribution on the membrane surface can be obtained. In addition, if three-dimensionally arranged in the membrane 1 15, the three-dimensional moisture content distribution in the membrane can be obtained.

[0089] The oscillating magnetic field (exciting oscillating magnetic field) applied by the planar coil 1 1 4 is R

It is generated by cooperation of F oscillator 102, modulator 104, RF amplifier 106, pulse control unit 108, switch unit 1601, and planar coil 1 14 In other words, the excitation high-frequency RF transmitted from the RF oscillator 102 is modulated by the modulator 104 based on the control by the pulse control unit 108 and becomes a pulse shape. The generated RF pulse is amplified by the RF amplifier 106 and then sent to the planar coil 1 14. The planar coil 1 14 applies this RF pulse to a specific part of the film. The planar coil 1 14 detects the echo signal of the applied RF pulse. This echo signal is amplified by the preamplifier 1 1 2 and then sent to the phase detector 1 10. The phase detector 1 1 0 detects this echo signal and sends it to the A / D converter 1 1 8. A / D converter 1 1 8 After the A / D conversion of the echo signal, it is sent to the calculation unit 130.

The switch unit 1 61 is provided at a branching unit that connects the planar coil 1 14, RF signal generation unit, and echo signal detection unit.

The RF signal generation unit includes an RF oscillator 102, a modulator 104, and an RF amplifier 106, and generates an RF signal that causes the planar coil 1 14 to generate an oscillating magnetic field for excitation. The echo signal detection unit is composed of a preamplifier 1 1 2, a phase detector 1 1 0, and an A / D converter 1 1 8, and detects the echo signal acquired by the planar coil 1 1 4, Is sent to the arithmetic unit 130.

[0091] The switch portion 1 61 is a planar coil 1 1 4? ¾ “Signal generator (RF amplifier)

1 06) and a second state in which the planar coil 1 14 and the echo signal detector (phase detector 110) are connected. That is, the switch unit 1 61 serves as such a “transmission / reception switching switch”.

[0092] By providing the switch portion 1 61 at the branch portion, the loss of the excitation high-frequency pulse signal applied from the planar coil 1 14 to the membrane 1 15 is reduced. As a result, the 90 ° pulse and 1 It becomes possible to control the pulse angle of 80 ° pulse accurately. Accurate control of the pulse angle is an important technical problem for reliably obtaining the compensation effect in the pulse echo method. In this embodiment, such a problem is solved by the arrangement of the switch unit 161.

[0093] In addition, the planar coil 1 14 for local measurement is miniaturized, and the reduction of noise during N MR reception is an important factor for ensuring the accuracy of measurement. When receiving NMR signals, the noise that enters the preamplifier 1 1 2 mainly includes an RF wave transmission system, and “RF wave leakage” or “large” from the RF amplifier 1 06 that amplifies the excitation pulse. There is noise generated by power amplifiers. When receiving an NMR signal, it is necessary to block the excitation wave leaking from the transmitter side with the switch unit 161 and receive the NMR signal with low noise. In the present embodiment, such a problem is solved by the arrangement of the switch portion 161.

[0094] The application of the excitation high frequency pulse and the detection of the echo signal have been described above. However, these can be realized by an LC circuit including a small coil (Fig. 8). In Fig. 8, the coil part (inductance part) of the resonance circuit is a small RF coil as described above. The nuclear magnetic resonance (NMR) method can measure atomic density and spin relaxation time constant by detecting the motion of nuclear magnetization as an NMR signal by the spin resonance phenomenon of a nucleus placed in a magnetic field. The spin resonance frequency in a magnetic field of 1 Tes Ia is about 43 MHz (this frequency band is called radio frequency), and in order to selectively detect that frequency band with high sensitivity, it is shown in Fig. 8. Such an LC resonant circuit is used.

[0095] The high frequency pulse for excitation applied by the planar coil 1 1 4 to the film 1 1 5 is, for example,

(a) 90 ° pulse and

(b) n 1 80 ° pulses applied at intervals of time 2, starting after the time of pulse (a)

The pulse sequence can consist of In order to clearly grasp the correlation between the T ₂ relaxation time constant and the amount of moisture in the film, it is important to properly apply the oscillating magnetic field. By using the pattern as described above, it is possible to clearly grasp the correlation between the ₂ relaxation time constant and the amount of moisture in the film.

[0096] Here, if the 90 ° pulse is in the first phase and the η 1 80 ° pulse is in the second phase 90 ° off the first phase, then Τ ₂ relaxation time constant And a clear correlation between the water content in the film can be obtained stably.

Note that when the planar coil 1 14 is used, it may be difficult to adjust the excitation pulse intensities (a) and (b). For example, in the region to be measured, that is, the region surrounded by the planar coil 1 14, there is a difference in the excitation method between the central portion and the peripheral portion, and the whole becomes a uniform excitation angle. In other words, it may be difficult to excite so that the intensity ratio of the excitation magnetic field in (a) and (b) is constant. If the excitation angle ratio in (a) and (b) varies, accurate T ₂ measurement becomes difficult.

[0098] Therefore, in such a case, the pulse control unit 1 08 force In addition to the 90 ° pulse (a), another sequence is executed at a time just before the 90 ° pulse (a), plus the step of applying the 180 ° pulse. Then, by comparing the behavior of the decay curves of the 180 ° pulse (b) corresponding to these two sequences, the excitation pulse intensities of the 90 ° pulse (a) and the 180 ° pulse (b) Whether or not is accurate. As a result, even if the excitation pulse intensity is deviated due to an abnormality in the device, the abnormality can be detected before the measurement is performed, and the measurement value can be made more accurate.

[0099] The apparatus configuration around the film has been described above. Next, the echo signal processing block will be described.

[0100] The calculation unit 1 30 calculates the T ₂ relaxation time constant from the intensity of the echo signal, and calculates the water content at a specific location in the film from the calculated Τ ₂ relaxation time constant.

[0101] Inside the arithmetic unit 1 30, first, an echo signal is acquired by the data receiving unit 1 2 0, and then a ₂ relaxation time constant is calculated by the relaxation time constant calculation unit 1 2 2.

[0102] T ₂ when relaxation time constant is calculated, the data is sent to a solvent amount calculating unit 1 2 4. The solvent amount calculation unit 1 2 4 accesses the calibration curve table (storage unit) 1 2 6 and acquires calibration curve data corresponding to the membrane. The calibration curve table 1 2 6, for each type of film, calibration curve data representing the relation between the water content and the T ₂ relaxation time constant in the film is stored.

[0103] The solvent amount calculation unit 1 24 uses the obtained calibration curve data and the ₂ relaxation time constant calculated as described above to calculate the amount of water in the film. The calculated water content is presented to the user by the output unit 1 3 2. There are no particular restrictions on the type of presentation, including display on the display, printer output, and file output.

[0104] In this embodiment, a planar coil is formed inside the film, on the film surface, or in the vicinity of the film.

Multiple 1 1 4 can also be arranged. Thereby, it is configured to be able to apply the excitation oscillating magnetic field and acquire the echo signal corresponding to the excitation oscillating magnetic field to a plurality of locations on the membrane. Solvent amount distribution calculation section 1 2 8 Based on the water content at the place, the water content distribution in the membrane is calculated. The output unit 1 32 outputs this moisture content distribution.

[0105] In the above apparatus, it is preferable to use a high-frequency pulse for excitation by the CPMG method. By doing so, a clear correlation between the T ₂ relaxation time constant and the amount of water in the film can be stably obtained.

[0106] Next, a method for measuring the amount of the protonic solvent (for example, moisture) of the membrane 1 15 by the CPMG method in the measuring apparatus 100 will be described.

In this measurement method, a film 1 15 is placed in parallel with the flow path forming surface of a permanent magnet 1 1 3 with a flow channel groove, and a specific location in the film 1 1 5 is detected using a nuclear magnetic resonance method. A method for locally measuring the amount of a protic solvent comprising the following steps. First, a static magnetic field is applied in the thickness direction of the film 1 1 5 by the permanent magnet 1 1 3 while flowing the fluid containing the above-mentioned protonic solvent in the flow channel of the permanent magnet 1 1 3 (step (S ) 1 02). In this state, an excitation oscillating magnetic field is sequentially applied several times to a part of the film 1 15 placed in a static magnetic field using an RF coil (planar coil 1 1 4). Acquire multiple echo signals corresponding to (S 104, 1st step above). Then, the T ₂ relaxation time constant is calculated from the intensity of these echo signals (S 1 06). Then, acquires data indicating a correlation between pro tons of Solvent volume and T ₂ relaxation time constant of the film 1 1 5, and a the data and S 1 0 6 T ₂ relaxation time constant calculated in, The amount of protonic solvent at a specific location in the membrane 1 15 is obtained (S 108, second step above). Then, the result is output (S 1 1 0).

[0107] In Step 104, an excitation high-frequency pulse is applied to the membrane. The excitation high-frequency pulse is a pulse sequence including a plurality of pulses, and an echo signal group corresponding to the pulse sequence is acquired. Is preferred. By doing so, it is possible to accurately determine the T ₂ relaxation time constant. The pulse sequence preferably comprises the following (a) and (b).

(a) 90 ° pulse and

(b) Starts after the elapse of the pulse of (a), and is applied at intervals of time 2 N 1 80 ° pulses

[0108] In order to clearly grasp the correlation between the T ₂ relaxation time constant and the amount of water in the film (the amount of the protonic solvent), it is important to appropriately apply the oscillating magnetic field. By using the pattern as described above, it is possible to clearly grasp the correlation between the ₂ relaxation time constant and the amount of moisture in the film. According to the method using the above pulse sequence, after a 90 ° excitation pulse, a 180 ° excitation pulse having twice the excitation pulse intensity is applied and the phase of the magnetization vector が is in the xy plane ( It reverses its phase disturbance on the way going disturbance on the rotating coordinate system), after 2 Te time can be obtained echo signal to get on and converges the phase T ₂ decay curves on.

[0109] Here, if the 90 ° pulse is in the first phase and the η 1 80 ° pulse is in the second phase that is 90 ° off the first phase, then Τ ₂ relaxation time constant And a clear correlation between the water content in the film can be obtained stably. The CPMG method is an example of a method for providing such a pulse sequence.

[0110] In the CPMG method, the magnetization vector is first tilted in the positive direction of the vertical axis by a 90 ° pulse, and then 1 80 ° excitation pulse is irradiated from the outside in the “axial direction” after a period of time. Invert the vector “with the Υ axis as the symmetry axis”. As a result, after two hours, the magnetization vector converges on the “positive direction” of the heel axis, and an echo signal with a large amplitude is observed. Furthermore, after 3 hours, the magnetization vector was irradiated with an external 1 80 ° excitation pulse in the “axis direction” and converged again on the “positive direction” of the axis, and a large amplitude after 4 hours. Observe an echo signal with Furthermore, continue to irradiate 1 80 ° pulse at the same two intervals. During this time, the peak intensity of the even-numbered echo signals of 2, 4, 6, 6 is extracted, and fitted with an exponential function to calculate Τ ₂ (lateral) relaxation time constant by the CPMG method. be able to.

[0111] In step 106, measure the relaxation time constant Τ ₂ by using the spin echo method.

The intensity S _SE of the echo signal when using spin echo is expressed by the following formula (A) when TR >> TE. [0112] [Equation 1]

S _SE = (x, y, z) '

[0113] where p is the density distribution of the target nuclide as a function of position (X, y, z), TR is the 90 ° excitation pulse repetition time (from about 10 Oms to 10 seconds), and TE is the echo Time (2 t, about 1 ms to 10 Oms), A is a constant that represents RF coil detection sensitivity and device characteristics such as amplifier.

[0114] From the echo signal group on the T ₂ attenuation curve and the above equation (Α), Τ ₂ relaxation time constant can be obtained.

To explain in detail, at intervals of 1, 80 ° pulses continue to be emitted, and the peak intensities of the even-numbered echo signals (2), (4), (6), and (6) are obtained. The peak intensity of the multiple echo signals gradually decreases with time. By fitting the intensities of multiple echo signals that decay with time with an exponential function, Τ ₂ relaxation time constant can be obtained from the above equation (Α).

[0115] In Step 1 08, the moisture content is calculated from the relaxation time constant. The water content and the T ₂ relaxation time constant in the film, with a positive correlation. With increasing water content T ₂ relaxation time constant is increased. Since this correlation varies depending on the type and form of the membrane, it is desirable to prepare a calibration curve for the same type of membrane as the measurement target membrane whose moisture concentration is known in advance. That is, the water content in pairs to a plurality of known standard samples film measurement of the relationship between water content and the T ₂ relaxation time constant, it is desirable to seek beforehand roughness a calibration curve showing the relationship. By referring to the calibration curve created in this way, the amount of moisture in the film can be calculated from the measured value of ( ₂₎ relaxation time constant.

[0116] The 緩和₂ relaxation time constant of the entire film is expressed by the following equation when expressed by the simplest equation.

1 / Τ ₂ (total) = (Amount of adsorbed water) Ζ (Adsorbed water Τ ₂ ') + (Amount of free water) / (Free water Τ ₂ '') ■ ■ ■ (1)

[0117] The observer measures this Τ ₂ (whole). Free water that fills the space As T ₂ (overall) increases as it increases, the amount of water in the high molecule can be determined from the measurement result of τ ₂ (overall).

[0118] Next, functions and effects of the present embodiment will be described.

In the present embodiment, permanent magnets 1 1 3 and planar coils 1 1 4 are used in specific shapes, and these are arranged in a specific positional relationship with the film 1 15. As a result, first, a fluid containing a protonic solvent is caused to flow into the recesses 10 5 of the permanent magnets 1 1 3 to form a distribution in the amount of the protonic solvent in the film 1 15, and the distribution thus formed is planar. Coil 1 1 4 can be measured. It is also possible to adjust the amount of the protonic solvent in the membrane 1 15 and measure the spatial distribution of the amount of the protonic solvent in the membrane 1 15 with the planar coil 1 14.

[0119] Therefore, according to the measuring apparatus 100, for example, the moisture content distribution in the film 115 can be measured on the spot. It is also possible to evaluate the water dispersion behavior in the in-plane direction of the membrane 1 15.

[0120] In addition, since the measurement region of the membrane 1 15 is included in the first region 1 07 and the second region 1 09, the local moisture content of the membrane 1 15 can be measured more. It can be performed with higher accuracy and good reproducibility. In particular, as described above with reference to FIG. 3 (b), the first region 10 07 that is the upper region of the convex portion 103 is perpendicular to the flow path forming surface of the permanent magnet 11 13. In the direction (z direction), there is a position where the static magnetic field becomes maximum. If measurement is performed at such a position, fluctuations in measurement values due to misalignment of the measurement area can be suppressed, and more accurate measurement can be performed.

[0121] For example, in the present embodiment, a magnetic field is applied only to a position and place where measurement is desired with respect to a thin sheet-like film 1 15 such as a polymer electrolyte, and a planar shape is formed in the gap between the magnet and the film. The local moisture content can be measured using an RF detection coil. In addition, local measurement can be performed in a shorter time than MRI measurement.

[0122] In addition, in the measuring apparatus 100, the NMR sensor can be made compact, so that the restriction on the installation location of the apparatus is eased. In addition, the price of equipment can be reduced. In addition, if the unitary device is a combination of the planar coil 1 1 4 and the permanent magnet 1 1 3, there is no need to align the two, and measurement can be performed easily. [0123] In the present embodiment, the permanent magnets 11 and 13 can be downsized. Here, in FIG. 9 and FIG. 11, the force that illustrates the configuration in which the uneven surface of the permanent magnet 1 1 3 is larger than the film 1 1 5, the permanent magnet 1 1 3 has a static magnetic field at the measurement location of the film 1 1 5. This is not limited to the case where the uneven surface is larger than the film 1 15. If a small magnet is used as a permanent magnet and a magnetic field is applied only to a part of the film, and an NMR signal can be received by a small RF detection coil only from the region where the magnetic field is applied, for example, the following advantages can be obtained. Is possible.

First, the dimensions of the membrane are arbitrary and are not limited to magnet dimensions.

Second, the magnet shape can be arbitrarily set. Therefore, for example, when applied to a fuel cell, a structure in which a gas flow path portion is incorporated in a magnet can be obtained.

Third, by using a magnet suitable for a thin sheet-shaped polymer electrolyte membrane and an RF detector coil, the local water content of the membrane can be measured at the position to be measured.

Fourth, local measurement is possible, and measurement is possible in a shorter time compared to MRI measurement.

Fifth, restrictions on the device materials that can be used are relaxed, and it is not necessary to use non-magnetic materials for all devices, so there is a possibility that they can be installed in fuel cells close to actual equipment. Sixth, the NMR sensor can be made more compact, easier to install, and less expensive.

The development of the N M R measuring device equipped with such a new permanent magnet 1 1 3 makes it possible to expand the application range of the N M R sensor.

[0124] The configuration of the measuring apparatus in the present embodiment may be as shown in FIG. 11, for example. FIG. 11 is a diagram showing another configuration of a measuring apparatus including permanent magnets 1 1 3 and planar coils 1 1 4.

[0125] (Fourth embodiment)

In the present embodiment, a solid polymer electrolyte fuel cell including the measuring apparatus 100 (FIG. 9) described in the third embodiment will be described.

[0126] An attempt to measure the water content of the solid polymer electrolyte membrane of a fuel cell by NMR When using a magnet that covers the entire film to be measured, all components of the fuel cell must be made of non-magnetic materials, and a device for NMR / MRI measurement is required. Need to make. However, its manufacture is difficult from the viewpoint of heat resistance and durability.

In addition, when using a magnet that covers the entire membrane, a large magnet is also incorporated into the actual fuel cell and used as a monitoring device. However, the magnet is too large to be mounted and cannot be a practical sensor.

On the other hand, the measuring apparatus 100 described above in the third embodiment has a structure in which the concave portion 105 of the permanent magnet 11 13 can be used as a gas flow path portion. Therefore, in the present embodiment, the permanent magnet 113 is incorporated into the fuel cell device as a part of the separator of the fuel cell so that the moisture content of the membrane 1 15, that is, the solid polymer electrolyte membrane 1 17 can be measured.

By incorporating the measuring device 100 into the fuel cell, it is possible to constantly monitor the water content of the polymer electrolyte membrane of the fuel cell and control so that the polymer electrolyte membrane can always maintain high conductivity. become able to. For this reason, it is possible to control the operation of the fuel cell so that the power generation efficiency of the fuel cell is maintained high.

FIG. 36 is a diagram showing the configuration of the fuel cell of the present embodiment.

The fuel cell 1 3 1 shown in FIG. 3 includes a measuring device 1 0 0, a cell 1 3 3, and an oxidant gas supply unit 3 2 for supplying an oxidant gas (for example, oxygen or air) to the cell 1 3 3, Fuel gas supply unit 3 3 for supplying fuel gas (for example, hydrogen gas) to the cell 1 3 3 and oxidant gas and fuel gas supply unit 3 supplied from the oxidant gas supply unit 3 2 to the cell 1 3 3 It has a steam mixing section 3 4, a steam mixing section 3 5, and a control section 3 6 that mix steam with fuel gas supplied from 3 toward the cells 1 3 3.

FIG. 37 is a cross-sectional view showing a configuration of cell 1 33 of fuel cell 1 31 shown in FIG.

Cell 1 3 3 is a solid polymer electrolyte membrane 1 1 7 that is a sample to be measured, and a solid Polymer electrolyte membrane 1 1 7 Catalyst layer 3 1 1 A and catalyst layer 3 1 1 B provided on both sides, Porous diffusion layer 3 1 2 A and diffusion layer 3 1 2 B, Separator 3 1 3 A and a separator 3 1 3 B.

[0130] The fuel electrode 3 1 4 is composed of the catalyst layer 3 1 1 A and the diffusion layer 3 1 2 A, and the oxidant electrode 3 1 is composed of the catalyst layer 3 1 1 B and the diffusion layer 3 1 2 B. 5 is configured.

[0131] In the separator 3 1 3 A, a groove serving as a fuel gas flow path is formed. A fuel gas containing water vapor is supplied to the flow path groove of the separator 3 1 3 A as a fluid containing a protonic solvent. Further, the separator 3 1 3 B is formed with a groove serving as a flow path for the oxidizing gas. An oxidant gas containing water vapor is supplied to the flow path groove of the separator 3 1 3 B as a fluid containing a protonic solvent.

[0132] In the fuel cell 1 3 1, the separator provided opposite to the fuel electrode 3 1 4 or the oxidant electrode 3 1 5, that is, the separator 3 1 3 A or the separator 3 1 3 B Of these, at least one is composed of the permanent magnet 1 1 3 described in the first embodiment. The flow path forming surface of the permanent magnet 1 1 3 is disposed opposite to the fuel electrode 3 1 4 of the fuel cell 1 3 1 and fuel gas is supplied to the recess 1 0 5 or the fuel cell 1 3 1 The oxidant gas is supplied to the recesses 10 5 so as to be opposed to the oxidant electrodes 3 15. The separator 3 1 3 A or the separator 3 1 3 B may be composed of a permanent magnet 1 1 3, or the permanent magnet 1 1 3 may be a separator 3 1 3 A or a separator. 3 1 3 May constitute part of B.

The oxidant gas supply unit 3 2 supplies oxidant gas to the cells 1 3 3. Further, the fuel gas supply unit 3 3 supplies fuel gas to the cells 1 3 3. Between the oxidant gas supply unit 3 2 and the cells 1 3 3, a water vapor mixing unit 3 4 is provided. In the water vapor mixing unit 3 4, water vapor is generated and mixed with the oxidant gas supplied from the oxidant gas supply unit 3 2 toward the cell 1 3 3. The oxidant gas thus mixed with the water vapor is supplied to the cell 1 3 3. Similarly, the water vapor mixing unit 3 5 is provided between the fuel gas supply unit 3 3 and the cell 1 3 3. It has been. In this steam mixing section 35, steam is generated and fuel The fuel gas supplied from the gas supply unit 3 3 toward the cell 1 3 3 is mixed with water vapor. Fuel gas mixed with water vapor is sent to cells 1 3 3.

Thus, the solid polymer electrolyte membrane 1 1 7 of the cell 1 3 3 is wetted by mixing the water vapor with the oxidant gas and the fuel gas.

[0134] In the case of measuring the amount of water in the solid polymer electrolyte membrane 1 1 7 of the cells 1 3 3, a plurality of planar coils 1 1 4 of the measuring device 1 0 4 are attached to the solid polymer electrolyte membrane 1 1 7. Touch the surface. As a result, the water content in the solid polymer electrolyte membrane 1 17 can be measured.

The control unit 36 is connected to the measuring device 100, the steam mixing unit 34, and the steam mixing unit 35.

In the control unit 36, the measurement result of the moisture content from the measuring device 100 and the distribution of the moisture content are obtained, and based on this measurement result, the steam mixing unit 34 and the steam mixing unit 35 generate the The water vapor mixing unit 34 and the water vapor mixing unit 35 are controlled so as to adjust the amount of water vapor supplied to the cells 13 3.

[0136] For example, when the cell 1 3 3 is generating power, the water in the solid polymer electrolyte membrane 1 1 7 is transferred to the fuel electrode as the hydrogen ions generated on the fuel electrode 3 1 4 side move. 3 1 Move from 4 side to oxidant electrode 3 1 5 side.

In addition, water is generated by the reaction of hydrogen ions and oxygen gas on the oxidizer electrode 3 1 5 side. Therefore, the water content in the solid polymer electrolyte membrane 1 17 may be excessive, particularly on the oxidant electrode 3 15 side. If the amount of water is excessive, water will aggregate in the flow path of the separator 3 1 3 B, impeding the flow of oxidant gas, which may reduce power generation efficiency.

On the other hand, when sufficient water vapor is not supplied to the solid polymer electrolyte membrane 1 1 7 and the solid polymer electrolyte membrane 1 1 7 is in a dry state, the proton conductivity decreases, and the cell 1 3 3 Power generation efficiency decreases. Therefore, it is not preferable that the solid polymer electrolyte membrane 1 17 is in a dry state and the proton conductivity is lowered.

[0137] Therefore, the control unit 36 obtains the moisture content distribution from the measuring device 100 and determines whether the moisture content value in the obtained distribution is within a predetermined range. That is, it is determined whether or not the solid polymer electrolyte membrane 1 17 is in an appropriate wet state. When it is determined that the predetermined range is exceeded, the control unit 36 requests the water vapor mixing unit 34 or the water vapor mixing unit 35 to reduce the amount of water vapor generated.

[0138] On the other hand, when it is determined that the moisture content in the moisture content distribution obtained from the measuring device 100 is out of the predetermined range and the moisture content is low, the control unit 3 6 The mixing unit 3 4 or the water vapor mixing unit 3 5 is requested to increase the amount of water vapor generated to prevent the solid polymer electrolyte membrane 1 1 7 from drying.

[0139] In the present embodiment, the control unit 36 adjusts the water vapor generation amount of both the water vapor mixing unit 34 and the water vapor mixing unit 35, and the water vapor supply amount to the cell 13 33. However, the present invention is not limited thereto, and for example, only the amount of steam generated in the steam mixing unit 35 and the amount of steam supplied to the cell 13 3 may be adjusted.

[0140] By using this, it is possible to perform N M R measurement of a plurality of polymer electrolyte membranes inside by installing a plurality of RF detection coils inside. For example, with the arrangement shown in Fig. 7 described later, the water content of multiple PEMs can be measured with a single magnet.

[0141] Next, functions and effects of the present embodiment will be described.

In the fuel cell 1 3 1, the permanent magnet 1 1 3 can be used as a separator, so that the solid polymer electrolyte membrane 1 1 7 The local moisture content distribution can be measured. Since the water content distribution in the solid polymer electrolyte membrane 1 1 7 can be measured in-situ, it is possible to control to improve the battery operating efficiency.

For example, if the amount of water in the solid polymer electrolyte membrane 1 1 7 at the top of the recess 10 5 is measured, the amount of water in the membrane in the vicinity of the region where fuel or oxidant is supplied into the membrane can be measured in real time. .

Further, by measuring the water content in the solid polymer electrolyte membrane 117 at the top of the convex portion 103, the diffusion state of the protonic solvent supplied from the channel groove can be grasped. [0142] For thin sheet-like samples such as polymer electrolyte membranes, an RF detection coil that applies a magnetic field only to the position and location where measurement is desired is installed without significantly changing the overall shape of the battery. It needs to be possible. In this respect, in the fuel cell of the present embodiment, the permanent magnet 1 1 3 is used as a separator, so that the solid polymer electrolyte membrane 1 1 7 force is arranged in parallel to the separator surface and the separator Located in the vicinity. Therefore, the configuration is suitable for the measurement of the solid polymer electrolyte membrane 1 17 disposed in the magnetic field formed in the vicinity of the flow path forming surface of the separator. In addition, by using a planar coil 1 1 4 as the RF coil, the coil can be easily laminated at a predetermined position near the surface of the solid polymer electrolyte membrane 1 1 7. It is possible to incorporate a device for measuring the water content without significantly changing the thickness. Thus, in the fuel cell 1 3 1, the configuration of the permanent magnet 1 1 3 and the planar coil 1 1 4 is adapted to the thin sheet-shaped solid polymer electrolyte membrane 1 1 7. It becomes possible to measure the local water content of the membrane at the position to be measured.

[0143] Further, in this embodiment, since the magnetic field is applied only to a part of the apparatus, restrictions on the apparatus material that can be used are alleviated, and it is not necessary to use all of the apparatus as a non-magnetic material. It has a suitable configuration.

[0144] In addition, in the fuel cell 1 3 1, the planar coil 1 1 4 is applied to the surface of the solid polymer electrolyte membrane 1 1 7 on the fuel electrode 3 1 4 side and the surface of the oxidant electrode 3 1 5 side, respectively. By touching, grasp the water content near the surface on the fuel electrode 3 1 4 side and the surface near the surface on the oxidizer electrode 3 1 5 side, and grasp the relationship between the water content near the surface of each electrode and the power generation efficiency. It can also be done. This makes it possible to determine whether the supply of water vapor from either the fuel electrode 3 1 4 side or the oxidant electrode 3 1 5 side is effective for power generation efficiency.

[0145] Further, the fuel cell 1 3 1 of the present embodiment has obtained useful data for searching for the cause of the decrease in power generation efficiency that occurs when the cell 1 3 3 is operated for a long time. Can be provided from the perspective of

[0146] Note that, in the fuel cell of this embodiment, a plurality of cells are stacked as shown in FIG. It may be a stacked type. In the case of a stack type fuel cell, the permanent magnet 1 1 3 can be a “permanent magnet with a gas flow path”, that is, a separator. FIG. 7 is a cross-sectional view showing a configuration of a stack type fuel cell including a plurality of cells including the solid polymer electrolyte membrane 1 1 7 a and the solid polymer electrolyte membrane 1 1 7 b. In FIG. 7, the permanent magnet 1 1 3 force is provided as the outermost separator. The permanent magnet 1 1 3 is provided opposite to the endmost cell (solid polymer electrolyte membrane 1 1 7 b) of the fuel cell stack, and the permanent magnet 1 1 3 is solid at the convex portion 1 0 3. The polymer electrolyte membrane 1 1 7 b is held, and fuel gas or oxidant gas flows into the recess 1 0 5. In FIG. 7, a separator 1 1 1 is a normal separator that does not have a permanent magnet 1 1 3.

[0147] From FIG. 3 (b), the magnetic field strength is about 0.2 to 0.3 TesIa even at a position away from the magnet (z> 1 Om m). With this magnetic field strength, NMRR measurement is sufficiently possible. Therefore, even if a magnet is placed at the extreme end of the fuel cell stack, a magnetic field is formed even inside the stack. Moreover, since the static magnetic field strength gradually decreases as the distance increases, the resonance frequency also decreases as the distance from the magnet increases. If the resonance frequency is different, interference of excitation pulses in a plurality of RF coils is less likely to occur.

[0148] Further, the use of the fuel cell of the present invention is not particularly limited. For example, it may be used not only as a battery but also as an evaluation device for the solid polymer electrolyte membrane 1 17.

As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are exemplifications of the present invention, and various configurations other than the above can be adopted.

[0150] For example, in the above embodiment, the measuring apparatus 100 includes a plurality of planar coils 1 1 4 and a plurality of planar coils 1 1 4 force films 1 1 5 And an echo signal corresponding to the oscillating magnetic field for excitation is acquired, and the amount of protonic solvent at a plurality of locations of the solvent amount calculation unit 1 2 4 force membrane 1 1 5 is calculated. Also good. By arranging planar coils 1 1 4 at multiple locations on the membrane 1 1 5 and measuring the amount of protonic solvent, the membrane It becomes possible to measure the distribution of the amount of 1 5 proton solvent in a shorter time. At this time, if a plurality of planar coils 1 1 4 are arranged on one first region 10 7 described above with reference to FIG. 6 or one second region 1 0 9, the film thickness direction can be increased. Suppresses the deviation of the static magnetic field intensity and enables more accurate multipoint measurement.

[0151] Further, in the above embodiment, a case where calculating the relaxation time constant T ₂ from the echo signal obtained by the CPMG method, calculates a pro tons of solvent amount in the film from the calculated T ₂ Although described in the example, it is also possible to obtain the amount of the protonic solvent from the signal intensity of the echo signal, as will be described later in the embodiment.

Incidentally, T ₂ do not depend sensitivity of the RF coil, the magnification of the amplifier, the apparatus configuration of the filter one characteristics, Ri by the calculating the pro ton solvent amount in the film from the T _2, pro tons solvent The amount can be calculated more easily. Further, when calculating the amount of the protonic solvent from the signal intensity, a calibration curve for associating the signal intensity with the amount of the protonic solvent may be obtained in advance by an experiment in accordance with the configuration of the measuring apparatus.

[0152] Further, in the above embodiment, for example, the following may be possible.

In other words, a gas flow path is attached to the magnet, a magnet with a gas flow path that can be incorporated into a fuel cell device is used as part of the fuel cell separator, and it is suitable for thin sheet polymer electrolyte membranes. The I e _ D type RF detection coil can measure the local water content of the membrane at the position (depth) to be measured.

Also, if a gas flow path magnet and a Doub Ie_D type coil are installed and measured at the position or location where the fuel cell is to be measured, it is only necessary to apply a magnetic field only to that location. This eliminates the need for a device other than the magnetic field application position to be made of a non-magnetic material, so that the NMR sensor can be applied to a more practical fuel cell device.

In addition, the NMR sensor can be made more compact, easier to install, and less expensive. In addition, if an integrated device combining an RF detection coil and a magnet is used, positioning of the two is unnecessary and measurement can be performed easily.

In addition, if this sensor is incorporated in a fuel cell, the water content of the polymer electrolyte membrane of the fuel cell can be constantly monitored and controlled so that it can always maintain high conductivity. It is possible to maintain high power generation efficiency.

[0153] In the above embodiment, the case where the amount of the protonic solvent in the solid polymer electrolyte membrane of the fuel cell is mainly exemplified, but the sample to be measured may be in the form of a membrane.

Further, the sample is not limited to a solid sample as long as it is in a film form, and may be, for example, a liquid containing a protonic solvent filled in a space having a predetermined thickness. Further, the sample is not limited to a film made of a solid polymer electrolyte or the like, and for example, a predetermined layer such as a catalyst layer may be formed on one side or both sides of the membrane. Example

[0154] (Example 1)

In this example, T ₂ (CPMG) values of samples A to C shown below were measured by the CP MG method using the measurement apparatus (third embodiment) shown in FIG.

(Sample Α) Liquid sample (Water)

(Sample Β) Polymer electrolyte membrane (Ρ ΕΜ)

(Sample C) Electrode ■ Polymer electrolyte membrane with catalyst (ΜΕΑ)

Was used. In this example, the permanent magnet shown in FIG. 2 was used. The material of the permanent magnet was Ν 巳 01 \ 1 Yawata Corporation ΕΟΜΑΧ—44Η.

[0155] (Sample Α) Liquid sample (Water)

The sample was prepared according to the following procedure. First, two pieces of cover glass (dimensions 18 mm x 18 mm, thickness 0.1 2 mm) were bonded with a gap of 0.5 mm to produce a container. Water was poured into the container and the container was sealed. The dimensions of the water part are 15 mm X 15 thickness 0.5 mm. This sample is Also called “0.5 mm thick water sample”.

[0156] A 0.5 mm thick water sample was regarded as PEM, and placed at the position of the solid polymer electrolyte membrane (PEM) 1 17 having the arrangement shown in FIG. Specifically, a Doub Ie_D type coil was placed on a permanent magnet with a gas flow path, and a “0.5 mm thick water sample” was placed on it.

[0157] In the NMR measurement, the magnet, coil, and sample were placed in a brass electromagnetic shield box and measured. This shield blocks external noise. C PMG measurement was performed using this device, and echo signals were acquired.

[0158] N MR measurement parameters were as follows. The 90-degree excitation pulse repetition time (TR) is 5 seconds, the 90-degree excitation pulse dummy count is 4, the NMR signal integration count is 64, and the resonance frequency is 13.07 MHz. The temperature of the 0.5mm thick water sample was about 25 ° C.

[0159] From the acquired echo signals, only the “even-numbered echo signal intensity” is extracted and shown in logarithmic plot as shown in Fig. 12. Based on this data, a straight line approximation was performed by the least square method, and T ₂ (C PMG) was calculated from the slope of the straight line. As a result, T ₂ (C PMG) was 24 ms.

[0160] C PMG measurement was performed by changing the distance between the Doub I e _ D type RF detection coil and the 0.5 mm thick water sample in 0.5 mm increments, and the relationship with the echo signal intensity was obtained. The results are shown in Figure 13.

Figure 13 shows that the echo signal intensity is maximum when the distance (gap) between the coil and the sample is 1 mm. Since the sample thickness is 0.5 mm, a distance of 1 mm means that there is a water sample between 1. Omm and 1.5 mm from the coil. This distance corresponds to the distance (1.2 mm) between the two semicircular coils of the Doub I e _D type coil. From this result, the Doub Ie_D type coil can measure the position (depth) separated by about the gap of the half-moon shaped coil, and can measure a little inside of the sample.

[0161] According to this example, the Doub I e _D type coil matches the geometric dimensions of the coil. It can be seen that the measurement depth changes. Therefore, it is possible to measure the thickness direction (depth direction) distribution in the polymer film by using a coil that matches the desired measurement depth.

[0162] (Sample B) Polymer electrolyte membrane (P EM)

As a polymer electrolyte membrane (PEM), Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd. was used. The dimension of PEM is 15mmX 15mmX thickness 0.5mm. The membrane was standardized by soaking in advance for 3 hours each in the order of 80 ° C 3% hydrogen peroxide, ion exchange water, 1 N hydrochloric acid, and ion exchange water.

[0163] Immediately before the experiment, the PEM immersed in ion-exchanged water was taken out, wiped with dry Kim Eve (registered trademark), and dried appropriately to adjust the water content of the PEM. Immediately after adjustment, the PEM was sandwiched between two cover glasses (dimensions 18 mm x 18 mm, thickness 0.12 mm), sealed with polyimide film to prevent drying. The mass of PEM was measured with an electronic balance, and it was confirmed that the water content did not change before and after NMR measurement.

[0164] The water content of PEM was calculated from the increase in mass by measuring the mass of PEM fully dried using an electronic balance and measuring the mass of PEM in the water-containing state.

In this embodiment, the water content of P EM 1 4. 9 - was performed by changing _{_{[H 2 0 / S0 3 H}} +] and _{1 2. 4 [H 2 0 /} S0 3 -H +] and. The PEM sample itself is the same sample, and only the water content is different.

[0165] Similar to the measurement of “0.5 mm thick water sample” for sample A, the PEM was placed at the position shown in Fig. 10 and the measurement was performed. Doub I e-D type coil is placed on the permanent magnet with gas flow path, and “Polymer electrolyte membrane (PEM)” is placed on it, and this is placed in a brass shield box. And obtained an echo signal

[0166] N MR measurement parameters were as follows. The 90-degree excitation pulse repetition time (TR) is 5 seconds, the 90-degree excitation pulse dummy count is 0, the NMR signal integration count is 64, and the resonance frequency is 13.07 MHz. The temperature of the polymer electrolyte membrane (PEM) was about 25 ° C. [0167] Using the same method as for the 0.5 mm thick water sample, only the “even-numbered echo signal intensity” was extracted from the echo signals obtained by PEM, and a logarithmic plot of it was shown in Fig. 1. Shown in 4. Based on this data, a straight line approximation was performed by the least square method, and T ₂ (CPMG) was calculated from the slope of the straight line. As a result, T ₂ (C PMG) was 34 ms.

[0168] The same measurement was performed for PEM with a water content of 12.4 [H ₂ 0 / S0 ₃ -H +]. Figure 15 shows the calculated T ₂ (CPMG) value by performing C PMG measurement three times with PEM of each water content. The straight line is based on the average of three T ₂ (CPMG) values.

[0169] From Fig. 15, it can be seen that the T ₂ (CPMG) value decreases as the water content decreases.

Also, as the moisture content of PEM decreased, the echo signal intensity also decreased. Figure 16 shows the relationship between echo signal intensity and water content obtained from two water content PEMs. The echo signal strength used here is the average of the third, fourth, and sixth echo signal strengths obtained by CPMG measurement. This averaging operation was performed in order to suppress variations in signal intensity.

[0170] From Fig. 15 and Fig. 16, it was found that a quantitative relationship between the water content of PEM and the echo signal intensity was obtained. Therefore, the moisture content of P E M can be converted based on the intensity of the echo signal.

[0171] (Sample C) Electrode ■ Polymer electrolyte membrane with catalyst (MEA)

Furthermore, T ₂ (CPMG) value acquisition experiments were conducted using an electrode-catalyzed polymer electrolyte membrane (MEA) with an electrode and catalyst applied to the surface of the polymer electrolyte membrane (PEM).

ME A was conducted with reference to Non-Patent Document 2. Specifically, a polymer electrolyte membrane manufactured by Asahi Glass Co., Ltd. was prepared by electrolessly plating Pt and Ir on the anode side and Pt on the cathode side. The dimensions of 1 \ 1 巳 8 are 17 mm x 15 mm square, 500; Um thickness

[0172] The standardized MEA was lifted from the ion-exchanged water just before the experiment. The water was wiped off by pressing against the tip. The water content of MEA just before the experiment is about 15 [H ₂ 0 / S0 ₃ -H +]. After wiping off the water, the MEA was quickly sandwiched between two cover glasses (dimensions 18 mm x 18 mm, thickness 0.1 2 mm) and sealed with a polyimide film to prevent drying.

[0173] Similar to the measurement of “0.5 mm thick water sample” for sample A, the MEA was placed at the position shown in FIG. A Doub I e-D type coil was placed on a permanent magnet with a gas flow path, and an “electrode / catalyst polymer electrolyte membrane (MEA)” was placed on it. This was placed in a brass shield box and CP MG measurement was performed to obtain an echo signal.

[0174] N MR measurement parameters were as follows. The 90-degree excitation pulse repetition time (TR) is 5 seconds, the 90-degree excitation pulse dummy count is 0, the NMR signal integration count is 64, and the resonance frequency is 13.07 MHz. Electrode ■ The temperature of the polymer electrolyte membrane with catalyst (MEA) was about 25 ° C.

In the same way as the 0.5 mm thick sample of sample A, only the “even-numbered echo signal intensity” was extracted from the echo signal acquired by ME A, and a logarithmic plot was shown. Figure 17 shows. Based on this data, a straight line approximation was performed by the least square method, and T ₂ (CPMG) was calculated from the slope of the straight line. As a result, T ₂ (CPMG) was 41 ms.

[0175] Based on the above, even when the sample was an electrode-catalyzed polymer electrolyte membrane (MEA), an appropriate T ₂ (CPMG) value could be measured.

Therefore, using a permanent magnet with a gas flow path and a Doub I e_D type RF coil manufactured so that it can be mounted in a fuel cell, CPMG measurement of a polymer electrolyte membrane (ME A) with electrode and catalyst can be performed and calculated. It can also be seen that the water content in the polymer electrolyte membrane can be estimated from the T ₂ (CPMG) value.

[0176] As described above, it was confirmed that a significant T ₂ (CPMG) value can be calculated by CPMG measurement for any of Sample A to Sample C.

[0177] It should be noted that Non-Patent Document 1 describes that the water content value of the solid polymer electrolyte membrane of the fuel cell is about 4 to 6 [H ₂ 0 / S0 ₃ -H +]. , And For example, if a change in water content of about 2 [H ₂ 0 / S0 ₃ − H +] can be detected, it can be suitably used for evaluation of a solid polymer electrolyte membrane of a fuel cell. In this respect, it can be seen from the above measurement results that the method of this example has a detection sensitivity that can sufficiently detect fluctuations in the water content of the solid polymer membrane.

[0178] In addition, the concentration per unit volume of the proton solvent in the fuel gas and the oxidant gas flowing in the separator flow channel during the operation of the fuel cell is equal to the concentration of the proton solvent in the polymer electrolyte membrane. As a result, the echo signal from the gas is negligibly small. For this reason, even if a gas containing a protonic solvent is allowed to flow through the flow channel groove of the permanent magnet, T ₂ (C PMG) measurement can be performed with the same measurement accuracy as when the gas is not flowed.

[0179] (Example 2)

In this example, the excitation magnetic field distribution _{χ χ} created by the Double-D type coil is theoretically analyzed, and the echo signal intensity distribution received by the coil when using the CPMG method S _SE , _Detect (equivalent to the measurement region) Was calculated quantitatively. In particular, when the distance L between the two D-shaped coils was changed, it was confirmed that the NMR signal acquisition region was separated from the coil. It was also shown that the measurement depth can be changed by adjusting the interval L.

[0180] The geometry of the Double-D coil is almost the same as the shape used in Example 1, the diameter D = 1 2mm, 3 turns, the distance between the two D coils is L = 1.2 mm It was. FIGS. 18 (a) and 18 (b) are diagrams showing the configuration of the Doub I e-D type coil analyzed in this example. Fig. 18 (a) shows the shape of the Double-D coil in the case of one turn. However, in actual calculations, as shown in Fig. 18 (b), three turns are used. did.

[0181] As a shape parameter, the distance L between two D-shaped coils was changed to 0.6 mm, 1.2 mm, 1.8 mm and 2.4 mm, and the NMR signal acquisition area (measurement area) received by the coil I examined the changes.

[0182] (Analysis of formation region of oscillating magnetic field for excitation)

First, the excitation magnetic field H _x (x _p , y _p , z _p ) formed by the three-turn Double-D coil having the geometry shown in Fig. 19 was analyzed under the following assumptions. (i) The coil wire diameter is zero (infinitely small wire diameter).

(i i) There is no skin effect when conducting. Since the wire diameter was set to zero, the effect of current flowing only on the coil surface was ignored.

(iii) In the 3-turn coil, three circles with different diameters are concentrically arranged as shown in Fig. 18 (b), and the interval between the first winding straight line conductors is L 1 and 2 turns in order from the largest arc. The distance between the straight line conductors is L 2 and the distance between the third winding line conductors is L 3 (L 1> L 2> L 3).

(i v) The coil is made of only conductive wire, and the coating film is ignored. Use vacuum values for dielectric constant and permeability.

(V) There is no sample (film). Use vacuum values for permittivity and permeability throughout the space.

(V i) Lead parts (wiring parts other than circular coils) are ignored.

[0183] Under the above assumption, the magnetic field H generated by the current I flowing through the conductor was calculated based on Bio-Savart's law. For the sake of explanation, the circular coil shown in FIGS. 20 (a) and 20 (b) will be described as an example. In FIG. 20, for the convenience of explanation, the planar shape of the coil is circular, but in the analysis, it is the shape shown in FIG. 18 (b).

[0184] When the circular coil is placed in a vacuum (magnetic permeability is ^{4 π X 1 0- 7 N /} A 2), the circular-shaped coil is positioned _{_{(x p, y p, z}} p) field make H (x _p , y _p , z _p ) is expressed by equation (2).

[0185] [Equation 2]

[0186] The coordinate system of the above equation (2) is as shown in Fig. 20, and the meaning of the symbols in the equation (2) is as follows.

H: Magnetic field strength at position r [A / m] (vector)

r: Position of point P in space (x _p , y _p , z _p ) [m] (vector) r ': position of point Q on the coil (x _q , y _p , z _q ) [m] (vector) I: current [A] (scalar)

t: Unit vector representing the direction of current flow (represents the shape of the coil at point Q. In Fig. 20, when the angle between point Q and the X axis is 0, t is equal to t = (sin 0, c ο s θ, 0)) [―] (vector)

Meaning of integration: Line integration is performed over the entire circumference of the coil. The magnetic field generated at point Ρ is obtained by moving point Q on the coil along the coil and integrating the magnetic field created at each point Q over the entire circumference of the coil (obtaining the sum).

[0187] In the case of a Doub I e-D type coil, a circular arc part and a straight line part are combined. Therefore, the coil shape was approximated as follows to make it almost the same as the shape of the Double-D coil.

In other words, the arc of the Double-D coil was divided into a number of sections and approximated as being represented by a straight line of length c L – d s [m] within the section. It is assumed that t in that interval changes smoothly with increasing angle 0. The straight part of the coil was divided as a straight element. This makes it possible to calculate Equation (2) numerically. In this example, one D-type coil on one side was divided into 16 straight lines, and the curved portion was also divided into 16 straight lines. This division method was the same for the first roll, the second roll, and the third roll (innermost). Figure 21 shows the parameters when dividing. Figure 18 (b) shows the overall shape of the divided elements with dots.

[0188] The current I flowing in the coil is 1 A, L = 1.2 mm, and the X-direction magnetic field strength H _x (x _p , y _p , z _p ) in Fig. 22 is Numerical analysis was performed. This is the X z plane with y _p = 0 mm. However, since this calculation is a singular point on the coil and cannot be calculated, the region within a radius of 0.05 mm near the coil was excluded from the calculation. FIG. 23 is a diagram showing the overall contour lines of a 3-turn Double-D coil. FIG. 24 shows the z-position distribution H _x (z _p ) of the magnetic field strength in the X direction. FIG. 26 and FIG. 27 are enlarged views of only the straight conducting wire portion (FIG. 25) of FIG. 23 and FIG. 24, respectively. Figure 23 and In Fig. 26, the cross section of the coil is indicated by a white circle (◯).

[0189] From Fig. 26 and Fig. 27, it can be seen that a magnetic field that can be considered uniform is formed around the apex where the magnetic field strength is highest. By disposing the coil so that this region is the measurement region for the Double_D type coil, variations in the excitation oscillating magnetic field can be suppressed, and more accurate measurement can be performed. It can be seen that the measurement area should be about 0.6 to 0.7 mm away from the coil.

[0190] The same magnetic field analysis was performed by changing the distance L between the two D-shaped coils to 0.6 mm, 1.2 mm, 1.8 mm, and 2.4 mm. The shape of the analysis model with the interval L of 1.2 mm corresponds to Fig. 18 (b). For these analyses, the analysis model shape of the Dou ble_D type coil is the same as diameter D = 1st volume diameter (D-1) = 12 mm, and 2nd diameter (D-2) and 3rd volume. The diameter (D-3) is also the same as the model shape shown in Fig. 18 (b). In each case, the number of element divisions for the straight line and the arc is the same. Therefore, as the interval L was increased, the straight line portions of each coil were separated from each other in the soil Y direction, the center angle of the arc portion was reduced, and the analysis points were re-probed.

[0191] As an example of the magnetic field analysis, the X-direction magnetic field strength distribution H _x (x _p , y _p , ₂ of the 3-turn Double-D coil when the distance L between the two D-type coils is 2.4 mm is shown in Fig. Fig. 29 shows the z-position distribution H _x (z _p ) of the magnetic field strength in the X direction when L is 2.4 mm.

[0192] Comparing Fig. 28 and Fig. 29 with the analysis result when L = 1.2 mm, when L = 2.4 mm, the measurement area where the magnetic field strength is maximum and the strength is uniform is the coil. It turns out that it is away from.

[0193] Figure 30 shows the z-position distribution H _x (0, 0, z _p ) of the magnetic field strength in the X direction when the distance L between the linear conductors of the two D-type coils of the Double-D type coil is changed. FIG. Fig. 30 shows that when the coil diameter (eg, D = 1 2mm) and the number of turns (eg, 3 turns) are unchanged, the measurement area becomes farther from the coil as the distance L between the two D-type coils increases. .

[0194] From the above analysis results, in the Double-D type coil, the distance between the two D type coils L It became clear that the depth of the measurement area can be changed by adjusting the.

[0195] (Analysis of formation area of echo-signal intensity distribution)

Next, using the analysis results of the magnetic field distribution above, both the “signal reception sensitivity of the Double-D coil” and the “relationship between the excitation angle α of nuclear magnetization and the signal intensity” based on an experimental relational expression. The measurement area of the surface coil was calculated according to the following procedure.

(i) Excitation angle distribution (χ _ρ , y _p , z) when the excitation angle at the position where Η _χ (0, 0, ζ _ρ ) is maximum on the central axis of the Double_D coil is 90 degrees _p ) was analyzed theoretically.

(ii) Echo signal intensity distribution S _SE (x _p , y _p , z _p ) using the experimental relational expression that the echo signal intensity S _SE in the spin echo method has an excitation angle of S _SE = (sin) ³ Was calculated. At this time, it was judged from the experimental results that the CPMG method and the echo method were the same.

(iii) The signal reception sensitivity of the Double-D coil is based on the magnetic field H _x (x _p , y _p , z

E) Received signal intensity distribution S _SE , _Detect

(x _P , y _P , z _p ) was calculated.

[0196] Fig. 31 shows the echo signal reception intensity distribution obtained by analyzing the case where the diameter D of the Double_D coil is 12 mm, the winding is 3 turns, and the distance between the two D coils is L = 1.2 mm. S _SE, illustrates _{_{_{Detect (x p, y p,}}} z p) a. In Fig. 31, the X z plane of only the central region of the Double-D coil is shown enlarged. In the figure, the cross section of the three straight line conductors of the Doubl eD type coil is shown schematically. The typical meaning is that the wire diameter is analyzed as zero.

[0197] Further, in Fig. 31, a region where the signal intensity is approximately 0.8 or more is shown surrounded by a dotted line. In the area surrounded by the dotted line, the echo signal is mainly acquired by the Double-D type coil, and this area can be regarded as the measurement area of the Double_D type coil in this case.

[0198] Figure 32 shows the echo signal received intensity distribution on the z-axis in Figure 31 S _SE , _Detect (0, 0, z _p FIG. In the case of this distribution, if the region where the signal intensity is approximately 0.8 or more as shown by the arrow is regarded as the measurement region with the Double-D coil, it is the same as the region surrounded by the dotted line in Fig. 31. Become.

[0199] Figure 33 shows an echo signal obtained by analyzing the case where the diameter D of the Double_D coil is 12 mm, the winding is 3 turns, and the distance between the two D coils is L = 2.4 mm. reception intensity distribution _{_{_{S SE, Detect (X p,}}} y p, Z p) is a diagram showing a. In FIG. 33, as in FIG. 31, the X z plane of only the central region of the Double-D coil is shown enlarged.

[0200] Also, in Fig. 33, the region where the signal intensity is approximately 0.8 or more is shown surrounded by a dotted line. In Fig. 33, it can be seen that compared to Fig. 31, the region where the signal strength is approximately 0.8 or more is widened, and at the same time, the region moves away from the coil.

[0201] Also, Fig. 34 shows the echo signal reception intensity distribution on the Z-axis in Fig. 33 S _SE , _Detect (0,

(0, z _p ). In Fig. 34, the range that can be regarded as the measurement area of the Double-D coil is indicated by arrows. Also in Fig. 34, compared to Fig. 32, it can be seen that the measurement area expands and at the same time moves away from the coil.

[0202] Figure 35 shows the echo signal reception intensity distribution S _SE on the z axis when the distance L between the two D-shaped coils is changed to 0.6 mm, 1.2 mm, 1.8 mm, and 2.4 mm. _det eot is a diagram showing a _{(0, 0, Z p)} .

From Fig. 35, when the coil diameter (eg, D = 12 mm) and the number of turns (eg, 3 turns) are unchanged, the normalized echo signal reception intensity on the vertical axis increases as the distance L between the two D-type coils increases. It can be seen that the region where the distribution S _SE , _Detect is greater than or _equal to 0.8 spreads and moves further away. From this, it can be said that the measurement area can be changed from a position close to the coil to a position far away by adjusting the distance L between the two D-type coils.

[0203] From the above results, when installing Double-D type coils in a fuel cell, for example, by installing multiple coils with different intervals L and switching and measuring individual coils from the transceiver, various Moisture content can be measured at the correct thickness position.

[0204] In this example, a three-turn coil was analyzed, but it was used in Example 1. For the five-turn coil, the width of the coil bundle is almost the same as that of the coil used in this example. If this width is about the same, it can be considered that a magnetic field similar to that of the 5-turn coil used in Example 1 is formed.

Claims

The scope of the claims

[1] An apparatus for locally measuring the amount of a protic solvent at a specific location in a film using a nuclear magnetic resonance method,

A permanent magnet for applying a static magnetic field to the film;

With

The measuring apparatus, wherein the film is provided in parallel to the flow path forming surface of the permanent magnet.

[2] In the measuring device according to claim 1,

The solvent amount calculation unit calculates a T ₂ relaxation time constant from the intensity of the echo signal, and calculates the amount of the protic solvent at a specific location of the film from the calculated ₂ relaxation time constant. measuring device.

[3] In the measuring device according to claim 1 or 2,

The measuring device, wherein the flow channel groove of the permanent magnet is composed of a plurality of groove portions, and the groove portions are arranged in parallel to each other.

[4] In the measuring apparatus according to claim 3,

The measurement apparatus, wherein the RF coil forms the excitation oscillating magnetic field having an amplitude in a direction in the flow path forming plane and perpendicular to an extending direction of the groove.

[5] The measuring device according to claim 4,

The RF coil includes a pair of coil portions, and forms the excitation oscillating magnetic field in a region sandwiched between the pair of coil portions,

When viewed from above the flow path forming surface of the permanent magnet, the region sandwiched between the pair of coil portions is within a single groove portion forming region or a region sandwiched between adjacent groove portions. Included measuring device.

[6] In the measuring apparatus according to any one of claims 3 to 5,

The RF coil is a planar coil in which a first coil part including a first linear region and a second coil part including a second linear region are connected,

The first coil part and the first nicole part have a conductive wire reversely wound, and the first linear region and the second linear region are arranged in parallel with the extending direction of the groove portion,

When viewed from above the flow path forming surface of the permanent magnet, a region sandwiched between the first linear region and the second linear region is included in a region sandwiched between the adjacent groove portions. , measuring device.

[7] In the measuring device according to any one of claims 3 to 5,

When viewed from the upper part of the flow path forming surface of the permanent magnet, a region sandwiched between the first linear region and the second linear region is included in a single groove forming region. measuring device.

[8] In the measuring device according to claim 6 or 7,

The RF coil is disposed between the flow path forming surface of the permanent magnet and the film;

A gap adjusting member having a specific thickness made of a non-magnetic material is disposed between the flow path forming surface of the permanent magnet and the planar coil and between the planar coil and the film. The measuring device.

[9] The measuring apparatus according to any one of [1] to [8], wherein the protic solvent is water.

[10] A fuel cell comprising the measuring device according to any one of claims 1 to 9.

[1 1] In the fuel cell according to claim 10, A fuel cell, comprising: a separator provided facing a fuel electrode or an oxidant electrode, wherein the separator includes the permanent magnet.

[12] The fuel cell according to claim 11, wherein

The fuel cell, wherein the flow path forming surface of the permanent magnet is disposed to face the fuel electrode of the fuel cell, and fuel gas is supplied to the flow channel.

[13] The fuel cell according to claim 11, wherein

The fuel cell, wherein the flow path forming surface of the permanent magnet is disposed opposite to the oxidant electrode of the fuel cell, and an oxidant gas is supplied to the flow channel groove.

[14] A film is arranged in parallel to the flow path forming surface of the permanent magnet in which the flow path grooves are formed, and the amount of the protonic solvent at a specific location in the film is locally determined using a nuclear magnetic resonance method. A method of measuring,

While flowing a fluid containing the protonic solvent in the flow channel groove of the permanent magnet, a static magnetic field is applied to the film by the permanent magnet, and a part of the film placed in the static magnetic field is applied. Applying a plurality of excitation oscillating magnetic fields sequentially using an RF coil, and obtaining a plurality of echo signals corresponding to the excitation oscillating magnetic fields;

Including the measuring method.

[15] In the measurement method according to claim 14,

The second step includes

A step of calculating a T ₂ relaxation time constant from the intensity of the echo signal, obtaining data indicating a correlation between the amount of the protonic solvent in the film and the ₂ relaxation time constant, and the data ( ₂₎ A step of determining the amount of the protonic solvent from the ( ₂₎ relaxation time constant calculated in the step of calculating a relaxation time constant ( ₂₎ .