JP2016145723A - Cell model, measurement system and simultaneous measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement technology of performing both NMR measurement and CV measurement in a measurement system capable of simultaneously measuring a current flowing through a polymer electrolyte membrane (PEM), moisture in PEM, and a state of hydrogen peroxide and a simultaneous measurement method used in the measurement system regarding a cell model for stimulating an operation state of a solid polymer fuel cell.SOLUTION: An internal electrode 40 is provided in a solid polymer electrolyte membrane 31 of a solid polymer fuel cell. A compact RF coil 37 is provided obtaining a nuclear magnetic resonance signal generated together with application of a vibration magnetic field for excitation to the solid polymer electrolyte membrane 31. A conductor 39 for CV measurement is provided which connects an anode-side electrode catalyst layer 34b and the internal electrode 40 to an external device for CV measurement. On the conductor 39, a filter is provided reducing the number of signals of frequency of a nuclear magnetic resonance signal. Thus, a conductor portion 39 for CV measurement in a static magnetic field is fixed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cell model that simulates the operating state of a polymer electrolyte fuel cell (hereinafter abbreviated as PEFC), and relates to a current flowing through a polymer electrolyte membrane (hereinafter abbreviated as PEM). The present invention relates to a measurement system capable of simultaneously measuring the state of moisture and hydrogen peroxide in a PEM, and a simultaneous measurement method used in the measurement system.

The inventors have proposed the techniques disclosed in Patent Document 1, Patent Document 2, and Non-Patent Document 1 as a technique for measuring the current flowing through the PEM and the amount of moisture in the interior.
In Patent Document 1, a nuclear magnetic resonance method (Nuclear Magnetic Resonance, hereinafter abbreviated as NMR, and a nuclear magnetic resonance signal obtained by this method is abbreviated as an NMR signal) is used as a measurement method. The technology disclosed in this document includes a small RF coil in a sample containing moisture and uses the CPMG (Carr-Purcell-Meiboom-Gill) method to improve the convergence of the obtained NMR signal and include it in the film. Determine the amount of protic solvent to be produced. The membrane contains the PEM targeted by the present application, and the protic solvent contains water. That is, by employing NMR, the amount of water in the PEM is obtained from the T ₂ relaxation time constant of the NMR signal.

In Patent Document 2, NMR is used to determine the current, water content, and water mobility in the PEM. In the technique disclosed in this document, the frequency shift between the excitation oscillating magnetic field and the nuclear magnetic resonance signal is used to derive the current, and the T ₂ relaxation time constant of the echo signal is used to derive the moisture amount.

  Also in Non-Patent Document 1, NMR is used to determine the current density in the PEFC, the spatial distribution of the moisture content in the PEM, and the temporal change. In this document, the configuration of the test apparatus is schematically shown in FIGS. 1 and 2. As can be seen from the figure, in NMR measurement, a PEFC single cell as a sample is placed in a static magnetic field. Furthermore, using a plurality of small RF coils arranged along the gas flow direction in the cell, the fuel gas (specifically, hydrogen gas) is supplied to the anode side, and the oxidizing gas (specifically, air). The spatial distribution of current density and moisture content is measured in the power generation state of the PEFC that supplies to the cathode side.

  On the other hand, as for hydrogen peroxide that may be generated in the PEM, the inventors also refer to Cyclic Voltammetry (hereinafter referred to as CV) of the sample in Non-Patent Document 2. In addition, it is proposed to obtain a hydrogen peroxide concentration by obtaining a potential sweep current signal obtained by this method (abbreviated as CV signal).

  In Non-Patent Document 2, with respect to a PEFC having an internal electrode in the PEM, hydrogen gas is supplied into the fuel gas flow passage and hydrogen peroxide is supplied into the oxidizing gas flow passage. Using the electrode as a reference potential electrode, a potential sweep is performed between the electrode and the internal electrode to obtain a CEM characteristic (specifically, a CV curve) of the PEM. In this document, the inventors confirmed that the amount of current at a specific potential (specifically 1.3 V) in the sweep process on the potential rising side has a positive correlation with the hydrogen peroxide concentration. Therefore, the hydrogen peroxide concentration can be obtained from the current value on the CV characteristic based on an index (a calibration curve or the like) obtained by this method.

WO2006 / 030743 WO2008 / 041361

Kuniyasu Ogawa et al., “Measurement of Spatial Distribution and Temporal Change of Current Density in Fuel Cell and Water Content in Solid Polymer Film by Small Surface Coil Using Nuclear Magnetic Resonance Method (1st Report: Relative Humidity of Fuel Gas and Effect of Utilization Rate on Water Content in PEM) ”, The Japan Society of Mechanical Engineers, Vol. 78, No. 788, April 2012, p. 211-221 Shigeki Yoneda and 6 others, “In-situ measurement in PEFC electrolyte membrane during power generation”, Abstracts of the 51st Battery Conference, November 11, 2010, p. 441

As described above, regarding the PEFC operated in a wet state, conventionally, the current (including spatial distribution in the PEM and changes over time) and the amount of moisture (including the spatial distribution in the PEM and changes over time) The hydrogen peroxide concentration (including the spatial distribution in the PEM, including the change over time) has been independently measured using different methods. It has never been measured simultaneously.
However, the former two are key information for studying the operating state of PEFC, and the latter causes deterioration of PEFC when it occurs, and is a critical factor that greatly affects the operating state, deteriorated state, etc. of PEFC. .

  Despite the above situation, it has not been actually confirmed how PEFC power generation state (current), water state (water content) and hydrogen peroxide generation state actually correlate.

  For example, when the utilization rate of hydrogen, which is a fuel gas, is increased, when the load on the fuel cell is changed, or when the humidification state of the PEFC is changed, the current, moisture, and hydrogen peroxide states are changed. It would be very useful for future PEFC development if it was possible to know precisely whether such behavior was exhibited.

  An object of the present invention is to obtain a measurement technique capable of performing both NMR measurement and CV measurement simultaneously and accurately with respect to PEFC operated in a wet state.

  Hereinafter, the “cell model” in which the present invention is placed in a static magnetic field and used for a test, “measurement system (whole system)” for performing NMR measurement and CV measurement using the cell model as a sample, and the measurement system Will be described in the order of “simultaneous measurement method” used in FIG.

  In this specification, a “static magnetic field” is a completely stable magnetic field as long as it is a magnetic field that is stable in time to such an extent that nuclear magnetic resonance signals (NMR signals) and current can be stably acquired. It may not be, and there may be some variation within the range.

In order to achieve the above object, a cell model that simulates the operating state of the polymer electrolyte fuel cell according to the present invention is configured as follows.
A solid polymer electrolyte membrane;
An anode-side electrode catalyst layer provided on the surface of the solid polymer electrolyte membrane and a cathode-side electrode catalyst layer provided on the back surface;
A fuel gas flow passage for supplying fuel gas from the anode side electrode catalyst layer side to the solid polymer electrolyte membrane;
An oxidizing gas flow passage for supplying an oxidizing gas from the cathode side electrode catalyst layer side to the solid polymer electrolyte membrane,
An internal electrode provided inside the solid polymer electrolyte membrane;
A small RF coil that applies an oscillating magnetic field for excitation to the solid polymer electrolyte membrane and acquires a nuclear magnetic resonance signal generated in the solid polymer electrolyte membrane,
In a state where the cell structure including the solid polymer electrolyte membrane, the two electrode catalyst layers, the internal electrode and the small RF coil is accommodated in a static magnetic field,
NMR measurement conductors that electrically connect each of the pair of terminals of the small RF coil to an NMR measurement external device outside the static magnetic field;
A conductor for CV measurement that electrically connects each of the anode-side electrode catalyst layer and the internal electrode to an external device for CV measurement outside a static magnetic field,
The CV measurement lead is provided with a filter for attenuating the frequency signal of the nuclear magnetic resonance signal,
A cell model in which at least a CV measurement lead portion located in the static magnetic field is fixed.

The cell model includes a solid polymer electrolyte membrane, an anode-side electrode catalyst layer, a cathode-side electrode catalyst layer, a fuel gas flow path, and an oxidizing gas flow path, thereby enabling operation as a fuel cell.
As for NNR measurement, NMR signals can be measured by connecting a small RF coil to an NMR measurement external device.
On the other hand, regarding CV measurement, a CV signal can be measured by connecting the anode side electrode catalyst layer and the internal electrode to an external device for CV measurement.

In addition to the above configuration, the cell model according to the present application includes a filter for attenuating a signal having the frequency of the nuclear magnetic resonance signal in the CV measurement lead.
By providing this filter, as will be described in the following embodiment, in the NMR signal obtained by NMR measurement, the noise intensity (standard deviation) of the noise portion can be reduced, and NMR measurement may be performed simultaneously with CV measurement. The S / N ratio can be secured to the extent that NMR measurement is performed independently, and measurement with high accuracy and reliability can be performed.

On the other hand, the position of at least the CV measurement lead wire located in the static magnetic field is fixed.
What is required to be fixed in this way is a new finding newly found by the present inventors, and is an important configuration for accurately measuring the state (for example, concentration) of hydrogen peroxide.
The inventors consider the reason why the position of the lead part for CV measurement is necessary as follows.
During CV measurement, current flows through the CV measurement lead. Since the cell model is arranged in the static magnetic field, when a current flows through the CV measurement conductor part located in the static magnetic field, an acting force is applied to the conductor part according to Fleming's left-hand rule. When the conducting wire portion is free without being fixed in position, the acting force causes the conducting wire portion to bend, deform, move, or vibrate. When such movement, vibration or the like occurs, the stray capacitance of the CV measurement lead increases or decreases, and the impedance of the lead changes. As a result, fine irregularities appear in the CV characteristic (CV curve) as shown in FIG. On the other hand, if the position of the CV measurement lead wire located in the static magnetic field is fixed, the change in impedance can be avoided, and fine irregularities do not occur as shown in FIG. 9B.
As described above, a CV curve without unevenness (CV characteristic) can be obtained by fixing the position of the CV measurement lead wire existing in the static magnetic field. As a result, for example, even when the state of hydrogen peroxide is obtained as a current flowing at a specific potential, it can be derived with high accuracy and high reliability.

  Therefore, by using the cell model according to the present application, NMR measurement and CV measurement can be performed simultaneously with high accuracy and high reliability.

  In the cell model described above, a housing that shields the cell structure from an electromagnetic wave from the outside in a state where the static magnetic field is applied to the cell structure, and a through-EMI filter as the filter is provided in the housing. Is preferred.

Even when the cell model according to the present application is used, it is necessary to block noise such as electromagnetic waves from the outside during measurement. Therefore, by providing a casing for electromagnetic wave shielding and performing only measurement so that only a static magnetic field is applied to the cell structure, measurement with high accuracy and reliability can be performed.
In addition, by using a penetrating EMI filter as a filter, noise components (especially frequency components of NMR signals) can be removed in the NMR measurement due to interference from the CV measurement side, and the NMR measurement can be performed satisfactorily. .

  Furthermore, it is preferable that the position of the CV measurement conductor to be fixed is fixed to the cell structure and fixed in the static magnetic field.

By adopting this fixed structure, it is possible to eliminate small irregularities that are problematic in the CV curve by using the cell structure.
Further, when the cell model is provided with a case for electromagnetic wave shielding for the purpose of eliminating the influence of electromagnetic waves entering the static magnetic field application site from the outside, the cell model may be fixed to this case.
Moreover, it is good also as what fixes the conducting-wire site | part for CV measurement in both the cell structure and the housing | casing for electromagnetic wave shielding.

Furthermore, in the cell model, it is preferable that the internal electrodes and the small RF coils are dispersedly arranged in the spreading direction of the solid polymer electrolyte membrane.
When this configuration is employed, NMR measurement and CV measurement can be performed spatially in the spreading direction of the solid polymer electrolyte membrane.

Furthermore, in the cell model, it is preferable that the internal electrodes and the small RF coils are respectively distributed in at least the fuel gas flow direction.
When this configuration is employed, NMR measurement and CV measurement can be performed spatially in the fuel gas flow direction, respectively.

The above is a description of the “cell model”, but a “measurement system” that executes NMR measurement and CV measurement as a whole will be described below.
The measurement system
The cell model that has been described so far,
A static magnetic field application device that applies a static magnetic field to the solid polymer electrolyte membrane in a state in which the cell model is accommodated therein,
An NMR measurement unit that applies an oscillating magnetic field for excitation to the solid polymer electrolyte membrane through the NMR measurement lead and the small RF coil, and acquires a nuclear magnetic resonance signal generated in the solid polymer electrolyte membrane; ,
A CV measurement unit that acquires a CV signal by performing a potential sweep for CV characteristic acquisition between the anode-side electrode catalyst layer and the internal electrode via the CV measurement lead;
In a state where a static magnetic field is applied to the solid polymer electrolyte membrane by the static magnetic field application device, the CV measurement unit can measure CV characteristics.

In this measurement system, the cell model to be a sample is placed under a predetermined static magnetic field by the static magnetic field application device, and NMR measurement can be performed satisfactorily.
Furthermore, the small RF coil provided in the cell model can be connected to the NMR measurement unit by the NMR measurement lead, and the excitation oscillating magnetic field can be applied to the PEM, and the nuclear magnetic resonance signal generated in the PEM can be acquired. .
On the other hand, the anode-side electrode catalyst layer and the internal electrode provided in the cell model are connected to the CV measurement section by a CV measurement lead, and the internal electrode is swept with the anode-side electrode catalyst as a reference potential. Characteristics can be obtained.

The basic configuration of NMR measurement is as follows.
For example, a pulsed oscillating magnetic field is applied from a small RF coil, and an FID (Free Induction decay) signal corresponding to the exciting oscillating magnetic field is acquired. Then, the real part and the imaginary part of the FID signal are obtained for the acquired current. At this time, it is only necessary that the magnetization vector is excited by an excitation pulse that can obtain a significant FID signal compared to noise, and the angle at which the excitation pulse excites the magnetization vector (the angle that is tilted with respect to the static magnetic field direction) is arbitrary. It is. By making this angle arbitrary, the recovery time of the magnetization vector related to the T ₁ relaxation time constant can be shortened, and the current can be measured in a short time by irradiating the excitation pulse with a shorter repetition time. It becomes.

  In addition, it is preferable that, for example, an excitation oscillating magnetic field is applied from a small RF coil in a predetermined sequence and an echo signal corresponding to the excitation oscillating magnetic field is acquired. This sequence is called a “pulse sequence” in the present application.

  Therefore, the “pulse sequence” in the present invention is a sequence that defines a timing diagram for setting the time and interval for applying the excitation oscillating magnetic field. Here, the timing diagram also includes a procedure table for performing necessary operations in time series.

In the following description, two main examples of pulse sequences are shown.
First pulse sequence The pulse sequence includes the following (a) and (b).
(A) a 90 ° pulse, and
(B) A 180 ° pulse applied after elapse of time τ of the pulse in (a).

  When the excitation oscillating magnetic field is a pulse sequence including the above (a) and (b) and the spin echo method for acquiring the real part and the imaginary part of the echo signal is used in the current derivation, the phase of the echo signal can be converged. it can. Further, as will be described later, measurement errors due to magnetic field inhomogeneities can be effectively reduced. For this reason, the measurement accuracy of the real part and the imaginary part of the nuclear magnetic resonance signal can be further improved.

In addition to the above pulse sequence, it is also preferable to execute another sequence in which a step of applying a 180 ° pulse is added at a time τ before the 90 ° pulse (a).
By comparing the intensity of the NMR signal acquired by the 90 ° pulse (a) and the intensity of the NMR signal acquired by appropriately selecting the time τ at the 180 ° pulse (b) with this pulse configuration, It can be determined whether the intensity of the oscillating magnetic field for excitation that corresponds to 90 ° and 180 ° accurately.

  In addition, the intensity of the two pulses (a) and (b) is 1 to 2, or the irradiation energy is 1 to 4, or the pulse application time is 1 to 2, and the magnetization vectors are 90 ° and 180 °, respectively. Excitation at ° can improve the accuracy and reproducibility of measured values.

Second Pulse Sequence The pulse sequence may include the following (a), (b), and (c).
(A) 90 ° pulse,
(B) 180 ° pulse applied after time τ of pulse (a), and (c) n 180 ° applied at intervals of time 2τ, starting from time 2τ of pulse (b). pulse.
Note that n is a natural number.

  By using the pulse sequence comprising the above (a) to (c), the current at a specific portion of the sample is measured using an echo signal corresponding to the pulse of (b) or (c), and (b) and ( The water content in the sample at the specific location can be accurately measured using a plurality of echo signals corresponding to the pulse c).

In addition to the above configuration, from the nuclear magnetic resonance signal acquired by the NMR measurement unit, an NMR information analysis unit for deriving one or more of the current state and moisture state of the cell model,
By providing measurement information obtained from each measurement unit by providing a CV information analysis unit for deriving the hydrogen peroxide state of the cell model from the CV characteristics measured by the CV measurement unit. The current state (current amount, current density, etc.) flowing through the PEM, the water state of the PEM (water amount, mobility of water molecules, etc.) and the hydrogen peroxide state (hydrogen peroxide concentration, hydrogen peroxide amount, etc.) Can be obtained.
Here, if the required current is regarded as a spatial distribution, the current density can be divided by the area where the current flows.
Alternatively, the hydrogen peroxide concentration may be the amount of hydrogen peroxide present in the entire solid polymer film.

In the measurement system equipped with this information analysis unit,
NMR measurement step of acquiring the nuclear magnetic resonance signal by the NMR measurement unit,
A CV measurement step of acquiring the CV characteristic by the CV measurement unit,
From the nuclear magnetic resonance signal acquired by the NMR measurement unit, an NMR information analysis step of deriving any one or more of the current state and moisture state of the cell model by the NMR information analysis unit,
From the CV characteristics measured by the CV measurement unit, a CV information analysis step of deriving the hydrogen peroxide state of the cell model by the CV information analysis unit is performed.
Simultaneous measurement of one or more of the current state and moisture state of the cell model and the hydrogen peroxide concentration of the cell model is measured.

Here, if the configuration in which the NMR measurement unit and the CV measurement unit work at the same time and the simultaneous measurement that executes the NMR measurement and the CV measurement at the same time is adopted sequentially, the behavior of the PEFC over time can be measured well. be able to.
In this case, the simultaneous measurement method described above is sequentially repeated.

  The above simultaneous measurement method can execute NMR measurement and CV measurement in a battery power generation state in which an electronic load is applied between the electrode catalyst layers.

Diagram showing the overall configuration of the measurement system The figure which shows the arrangement configuration of the small RF coil and internal electrode in a cell model The figure which shows the fixed structure of the filter and lead part for CV measurement in a cell model Flow chart showing measurement procedure in measurement system Principle diagram explaining the principle of NMR signal acquisition Principle diagram explaining compensation function of CPMG method Diagram showing NMR signals (eco-signals) obtained from PEMs with different water contents The figure which shows the CV curve obtained from PEM of different hydrogen peroxide concentration The figure which shows the CV curve with the case where it does not fix and the case where it does not fix the lead part for CV measurement located in the housing

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

  The present application relates to a measurement system 100 that enables simultaneous measurement of an NMR signal and a CV curve (CV characteristic) of a sample PEM (or a PEFC equipped with the PEM). Both a measurement system 101 for measurement and a measurement system 102 for CV measurement are provided.

In NMR measurement, it is necessary to position the sample in a static magnetic field.
In this embodiment, the example which uses the permanent magnet 1 as a static magnetic field application apparatus is shown. As shown in FIG. 1, the permanent magnet 1 is formed in an approximately U-shape that is open upward and has an intermediate portion, and includes a static magnetic field application region 2 inside.

  In the present measurement system 100, the system functional part that is housed in the static magnetic field application region 2 and is a measurement target at the time of simultaneous measurement is referred to as a cell model 30, and is positioned outside the static magnetic field application region 2. A system functional part that performs NMR measurement and CV measurement on the sample and derives the current, water content, and hydrogen peroxide concentration in the sample PEM from the measurement result is referred to as an external device 50.

As shown in FIG. 2, the cell model 30 includes a PEM 31 to be measured (or a PEFC 32 including the PEM 31), and operates as a fuel cell by being supplied with a fuel gas and an oxidizing gas. The generated power is supplied to the electronic load 36. Of course, even in a state where power generation is not performed, it is possible to perform NMR measurement and CV measurement with the PEFC 32 in a predetermined wet state.
The main part of the cell model 30 is housed in an electromagnetic shielding box (hereinafter simply referred to as a casing 33) covered with copper foil for the purpose of reducing noise during NMR measurement.
The housing 33 is shaped to shield the electromagnetic wave at the release portion of the permanent magnet 1 in a state where the cell model 30 is housed in the concave portion of the permanent magnet 1, and is an opening through which the static magnetic field H of the permanent magnet 1 is transmitted ( (Not shown).

Returning to FIG. 1, the external device 50 includes a gas supply external device 51 for operating the battery of the cell model 30, an NMR measurement external device 52, and a CV measurement external device 53.
The cell model 30 and the external devices 51, 52, and 53 are configured such that the cell model 30 (specifically, gas flow passages 42 and 43, which will be described later) and the gas supply external device 51 are gas supply and discharge gas conduits 51a. The cell model 30 (specifically, a small RF coil 37, which will be described later) and the NMR measurement external device 52 are connected by an NMR measurement lead wire 52a. The electrodes 34b, 40) and the CV measurement external device 53 are connected by a CV measurement lead 53a.
The above is the main configuration of the measurement system.

  Hereinafter, the simultaneous measurement using the cell model 30, the external devices 51, 52, and 53 and the measurement system 100 and the derivation of the state information of the PEM 31 (or the PEFC 32 including the PEM) will be described.

(Cell model 30)
PEFC
As is well known, the PEFC 32 includes a PEM 31, electrode catalyst layers 34 provided on the front and back surfaces of the PEM 31, and a pair of gas diffusion layers 35 (Gas Diffusion Layer hereinafter referred to as GDL). It is configured. In this embodiment, the PEM 31 is a Nafion 117 (product name) manufactured by Du Pont, the electrode catalyst layer 34 is a Pt catalyst layer, and the GDL 35 is a carbon mesh having a thickness of 400 μm manufactured by Toray. The current was taken out from the electronic load 36 from the GDL 35.
Further, as a fuel gas and oxidizing gas supply system, a fuel gas flow passage 42 and an oxidizing gas flow passage 43 are provided outside the GDL 35. The gas is supplied to and discharged from the flow passages 42 and 43 in a predetermined humidified state.

As shown in FIG. 2, a plurality of small RF coils 37 are arranged between the cathode-side electrode catalyst layer 34a and the GDL 35a as an NMR measurement device provided in the cell model 30. The plurality of small RF coils 37 are arranged in a distributed manner at least in the direction in which the oxidizing gas flows (in the vertical direction and the front and back directions in FIG. 2 and also in the direction in which the fuel gas flows).
Each small RF coil 37 is connected to an NMR measurement external device 52 by a coaxial cable 38. The coaxial cable 38 corresponds to the “NMR measurement lead wire 52a” of the present application.

CV Measurement As a device for CV measurement provided in the cell model 30, a plurality of internal electrodes 40 are provided in the PEM 31 as shown in FIG. Specifically, these electrodes 40 were Pt electrodes. The CV characteristic is measured using the internal electrode 40 with the electrode catalyst layer 34b on the anode side of the PEFC 32 as a reference potential portion. The plurality of internal electrodes 40 are also dispersedly arranged at least in the fuel gas advection direction (the vertical direction and the front-back direction in FIG. 2).

  In the present embodiment, the position of the internal electrode 40 in the thickness direction of the PEM 31 is the anode electrode catalyst 34b side. This is because the generation rate of hydrogen peroxide is taken into consideration. Hydrogen peroxide is considered to be generated at the interface between the PEM 31 and the electrode catalyst layer 34. When considering the cathode electrode catalyst side as a consideration, it may naturally be arranged on the cathode electrode catalyst side. Furthermore, when the diffusion of hydrogen peroxide in the PEM 31 is taken into consideration, the center in the thickness direction of the film may be used.

Each internal electrode 40 and the anode side electrode catalyst layer 34b or the GDL 35b having the same potential were electrically connected to an external device 53 for CV measurement through a filter 41 with a conducting wire. This conducting wire corresponds to the “CV measuring conducting wire 53a” of the present application.
As will be described in detail later, the configuration of the filter 41 and the partial portion 39 of the CV measurement lead wire 53a is indispensable when performing NMR measurement and CV measurement simultaneously.

(External device)
Gas Supply External Device As the gas supply external device 51, both a fuel gas supply / recovery mechanism 51h and an oxidizing gas supply / recovery mechanism 51o are provided.
The fuel gas supply / recovery mechanism 51h is connected to the fuel gas flow passage 42 in the cell model 30, supplies the fuel gas to the PEFC 32, and recovers the fuel gas that has not been used for power generation.
The fuel gas supply / recovery mechanism 51h includes a fuel gas tank 54h, a humidifying mechanism 55h for humidifying the supplied fuel gas in a predetermined humidified state, and a supply gas amount adjusting mechanism 56h for adjusting the amount of the supplied fuel gas. .

The oxidizing gas supply / recovery mechanism 51o has basically the same configuration, and is connected to the oxidizing gas flow passage 43 in the cell model 30 to supply the oxidizing gas to the PEFC 32 and not to generate power. Collect oxidizing gas.
An oxidizing gas tank 54o, a humidifying mechanism 55o for humidifying the supplied oxidizing gas into a predetermined humidified state, and a supply gas amount adjusting mechanism 56o for adjusting the amount of the oxidizing gas to be supplied are provided.

Hereinafter, the NMR measurement external device 52 and the CV measurement external device 53 will be described.
In FIG. 1, the configuration of the NMR measurement external device 52 and the CV measurement external device 53 is shown divided into functional parts.
Each component of the external measuring devices 52 and 53 is realized by an arbitrary combination of hardware and software, mainly a CPU, a memory, a program for realizing each component loaded in the memory, and the like. And it will be easily understood by those skilled in the art that there are various modifications in the implementation method and apparatus.

NMR Measurement External Device The NMR measurement external device 52 includes an NMR measurement unit 52b and an NMR information analysis unit 52c as functional parts.
The NMR measurement unit 52b applies an excitation oscillating magnetic field to the PEM 31 via the NMR measurement lead wire 52a and the small RF coil 37, and acquires a nuclear magnetic resonance signal (NMR signal) generated in the PEM 31 according to the application. A resonance circuit 52d is provided at a connection portion of the NMR measurement unit 52b with the small RF coil 37 so that impedance adjustment can be performed satisfactorily.
The NMR information analysis unit 52c derives one or more of the current and moisture content of the cell model 30 from the nuclear magnetic resonance signal acquired by the NMR measurement unit 52b according to the analysis principle described later.

Hereinafter, the measurement of current and the measurement of moisture content will be described in this order.
In the description, the flowchart shown in FIG. 4 is also referred to.
This flowchart is a flowchart showing a measurement procedure of the entire measurement system according to the present application, in which the left side is a current derivation flow, the center is a moisture amount derivation flow, and the right side is a hydrogen peroxide concentration derivation flow.

  Furthermore, FIG. 5 shows a “principle diagram for explaining the principle of acquiring NMR signals by NMR” and a “principle diagram for explaining the compensation function of the CPMG method” shown in FIG. FIG. 7 shows the form of the NMR signal observed when NMR measurement is performed. The pulse sequence generated from the small RF coil 37 and the echo that constitutes the main part of the NMR signal as time elapses (horizontal axis). It shows that the noise part after the signal E is observed. The pulse sequence shown in FIG. 7 is an example in which the 90 ° pulse and the 180 ° pulse shown in FIG. 5 are combined.

  In the following description, the explanation points of the operations that the NMR measurement unit 52b and the NMR information analysis unit 52c respectively handle are pointed out as appropriate.

(A) Measurement of current In NMR measurement, the movement of nuclear magnetization is detected as an NMR signal by the spin resonance phenomenon of a nucleus placed in a magnetic field. If the NMR signal is measured using the small RF coil 37, the local NMR measurement of the coil peripheral part can be performed.
When the outline of the measurement of the local current is described, the difference between the frequency of the nuclear magnetic resonance signal and the frequency of the oscillating magnetic field for excitation is obtained, and the current at a specific portion of the sample can be obtained from the obtained difference.

(I) Application of excitation high-frequency pulse and acquisition of NMR signal An excitation high-frequency pulse for irradiating the target nucleus in the PEM 31 is applied as the excitation oscillating magnetic field. Correspondingly, the NMR signal emitted from the measurement target nucleus in the PEM 31 can be acquired by the nuclear magnetic resonance phenomenon caused by the excitation oscillating magnetic field (FIG. 4, # 102-1).

  Specifically, the NMR signal is an echo signal E corresponding to a high frequency pulse for excitation. The echo signal E preferably has a converged phase. Further, the high frequency pulse is applied in a pulse sequence in which the phases of the echo signals are matched as described above. Specific examples of the pulse sequence employed in the present embodiment will be described later with reference to FIGS.

The NMR signal is detected by separating a real part and an imaginary part by a phase sensitive detection method. Thereby, it is possible to easily derive the frequency shift that is the difference between the frequency of the nuclear magnetic resonance signal and the frequency of the excitation oscillating magnetic field.
The above is the function of the NMR measurement unit 52b. Thereafter, the obtained NMR signal is analyzed by the NMR information analysis unit 52c, and a local current in the vicinity of the small RF coil 37 (a current amount or a current density can be obtained) can be obtained.

(Ii) Derivation of frequency shift A frequency shift which is a difference between the frequency of the acquired NMR signal and the frequency of the oscillating magnetic field for excitation is obtained (# 103-1f in FIG. 4).

  Specifically, the phase difference Δφ is obtained by deriving the arctan of the real part and the imaginary part of the echo signal acquired by the phase sensitive detection method. Then, the frequency shift Δω is converted as a phase difference Δφ per unit time.

(Iii) Derivation of current A current is derived from the acquired frequency shift Δω.

When a current flows through the measurement target, a magnetic field H _{j that} is directly proportional to the current _j is generated from Bio-Savart's law. The magnetic field strength is inversely proportional to the distance r ⁿ (where n is a power) between the position where the current flows and the measurement position.

  On the other hand, in the nuclear magnetic resonance phenomenon, the resonance frequency ω of nuclear magnetization is directly proportional to the magnetic field strength. When the magnetic resonance signal is acquired by the small RF coil 37, the magnetic field intensity in the region measured by the small RF coil 37 is indirectly measured as the magnetic resonance frequency ω.

In a static magnetic field H (magnetic field vector H ₀ ) that is stable both spatially and temporally created by the permanent magnet 1, if the current _j is made to create the magnetic field vector H _j , the magnetic field strength H _j at a certain position is The combined vector (H ₀ + H _j ) of both. Since the magnetic field vector H ₀ is constant, if the resonance frequency ω of the nuclear magnetization was increased or decreased by Δω, the magnetic field intensity H _j at a certain position it will be related to the current j and the distance r ^n.

  Therefore, the current j flowing through the sample can be obtained from the obtained frequency shift Δω by acquiring the relationship between the current j flowing in the vicinity of the small RF coil 37 and the frequency shift Δω in advance by an experimental method or the like. (FIG. 4 # 104-1i).

  As in this embodiment, if a plurality of small RF coils 37 are arranged on the sample and the increase / decrease Δω of the resonance frequency of nuclear magnetization is measured at a plurality of positions in the PEM 31, the current j and the position r through which it flows are obtained. It can be obtained by inverse problem analysis.

  At this time, the NMR detection method has a frequency resolution on the order of ppm, and this makes it possible to capture changes in magnetic field strength with high resolution and high sensitivity. For example, when the frequency of the excitation oscillating magnetic field is 43 MHz, a resolution of about 10 Hz is sufficiently obtained.

Hereinafter, specific examples of (i) application of excitation high-frequency pulse (sequence pulse) will be shown.
In actual measurement, magnetic field non-uniformity caused by sample and apparatus characteristics occurs, and a frequency shift cannot be obtained accurately. Therefore, in the present embodiment, the spin echo method is used, and the excitation high-frequency pulse is set to a pulse sequence including a plurality of pulses including, for example, the following (a) and (b) (see FIG. 5).
(A) a 90 ° pulse, and
(B) 180 ° pulse applied after elapse of time τ of the pulse of (a) This pulse sequence is the first pulse sequence described above.

  When an excitation oscillating magnetic field according to the pulse sequences (a) and (b) is applied, the phase of the echo signal E converges, and the measurement error due to such magnetic field non-uniformity is effectively reduced. In addition, since the variation in the phase of the corresponding echo signal E can be suppressed, the current can be obtained more accurately.

As shown in the lower part of FIG. 5, the resonance-excited magnetization vector M _-y relaxes with time. At this time, the time change of the actually observed magnetic resonance signal is relaxed by the spin-lattice relaxation time constant T ₁ and another time constant T ₂ ^* which cannot be expressed only by the spin-spin relaxation time constant T _2. To go. This state is shown immediately after the 90 ° pulse as the time variation of the signal intensity at the bottom of FIG. In general, the actually measured magnetic resonance signal intensity indicated by the wavy line is rapidly attenuated, and its time constant T ₂ ^* is shorter than T ₂ . The reason why the decay signal actually observed decays faster than the decay curve due to T ₂ relaxation is because of the non-uniformity of the external static magnetic field created by the static magnetic field magnet and the non-uniformity of the magnetic field in the sample due to the magnetic properties and shape of the sample. This is because a uniform magnetic field is not ensured over the entire sample due to uniformity or the like. Such time change of the actually measured magnetic resonance signal is referred to as free induction decay, “Free Induction decay” in English notation, and “FID” in abbreviated English notation.

There is a “spin echo method” as a method for correcting a phase shift due to magnetic field inhomogeneity as a sample or device characteristic. As shown in the upper part of FIG. 5 or FIG. 7, after the 90 ° pulse τ time, a 180 ° pulse having twice the excitation pulse intensity is applied, and the phase of the magnetization vector M is on the xy plane. The phase disturbance is reversed in the middle of the disturbance, and after 2τ time, the phase is converged to obtain an echo signal E on the T ₂ attenuation curve.

When the direction along the static magnetic field is the Z direction for convenience, the 180 ° pulse applied in the above (b) can be used in either the X direction or the Y direction.
Alternatively, a 180 ° pulse may be further applied after the elapse of time 2τ in (b), and current measurement may be performed using an echo signal corresponding thereto. However, when current measurement is performed using a plurality of echo signals, it is effective to irradiate the 180-degree excitation pulse in the Y-axis direction a plurality of times so that the strongest possible echo signal can be observed. The reason is explained by the movement of the magnetization vector in FIGS. 6A to 6D described later.

  By adopting these methods, the phase of the magnetization vector is converged and the strongest possible echo signal E is obtained. With such an echo signal E, it is possible to detect a real part and an imaginary part of the NMR signal with higher accuracy, and to reliably determine the amount of phase shift from the reference frequency. As a result, the NMR information analysis unit 52c can accurately derive the current from the frequency shift.

(B) Measurement of moisture content Regarding the measurement of moisture content, the function of the NMR measurement unit 52b and the function of the NMR information analysis unit 52c are basically the same. However, as described below, the NMR information analysis unit 52c derives a T ₂ (lateral) relaxation time constant by a CPMG (Carr-Purcell-Meiboom-Gill) method, which will be described later, and then uses a calibration curve to calculate the sample. Deriving local water content.

  In the following description, detailed description of functions common to the above-described current measurement is omitted as appropriate.

(I) Application of high frequency pulse for excitation and acquisition of NMR signal

The pulse sequence includes the following (a), (b) and (c).
(A) a 90 ° pulse, and
(B) 180 ° pulse applied after time τ of pulse (a), and (c) n 180 ° applied at intervals of time 2τ, starting from time 2τ of pulse (b). Pulse (n is a natural number)
The above (a) and (b) are common to (A) current measurement.
This pulse sequence is the second pulse sequence described above.

By applying the excitation oscillating magnetic field according to the pulse sequences of (a) to (c) above, the phase of the echo signal E converges better, and the measurement error due to the non-uniformity of the magnetic field is effectively reduced. . Moreover, since the dispersion | variation in the phase of the corresponding echo signal E can be suppressed, a moisture content can be calculated | required correctly (FIG. 4 # 102-1).
The above is the function of the NMR measurement unit 52b. Hereinafter, the obtained NMR signal is analyzed by the NMR information analysis unit 52c, and the amount of moisture in the vicinity of the coil can be obtained.

Hereinafter, the usefulness of the first pulse sequence will be described in more detail with reference to FIGS. 6A to 6D, and the second pulse sequence used for measuring the moisture content will be described.
First pulse sequence A hydrogen nucleus placed in the static magnetic field H has a net magnetization vector in a direction along the static magnetic field (for convenience, the Z direction), and has a specific frequency (this is called a resonance frequency). Is irradiated from outside in the X-axis direction perpendicular to the Z-axis, the magnetization vector is tilted in the positive direction of the Y-axis, and a nuclear magnetic resonance signal (NMR signal) can be observed. At this time, the high-frequency pulse for excitation in the X-axis direction irradiated for obtaining the NMR signal having the maximum intensity is a 90 ° pulse. Then, after the magnetization vector is tilted in the positive direction of the Y axis by a 90 ° pulse, a 180 ° pulse is irradiated from the outside in the “Y axis direction” after τ time, and the magnetization vector is set to “with the Y axis as the symmetry axis”. Invert. As a result, after 2τ time, the magnetization vector converges on the “positive direction” of the Y axis, and an NMR signal having a large amplitude is observed.

  Thus, since the magnetization vector is inverted “with the Y axis as the axis of symmetry”, the following compensation function appears. FIG. 6A to FIG. 6D are diagrams for explaining the compensation function of the spin echo method. The coordinates shown in the figure are a rotating coordinate system.

  Let P and Q be considered as nuclear magnetization in a small region in the sample where the inhomogeneity of the static magnetic field H can be ignored. Let the magnetic field at P be stronger than the magnetic field at Q. At this time, as shown in FIG. 6A, when a 90 ° pulse is applied in the x′-axis direction, the nuclear magnetization of P and Q starts precession from the same location (y′-axis) in the rotating coordinate system. As time passes, the phase of P advances from the phase of Q (FIG. 6B).

  Therefore, when a 180 ° pulse is applied in the y′-axis direction after a time τ has elapsed from the 90 ° pulse, the nuclear magnetization of P and Q rotates 180 ° around the y′-axis, and before the pulse is applied, y ′ The arrangement is symmetric with respect to the axis (FIG. 6C).

  In this arrangement, since the nuclear magnetization P having a more advanced phase has a phase delayed from Q, both nuclear magnetizations simultaneously reach the y ′ axis at the time when the time τ has passed since then ( FIG. 6 (d)).

  Since such a relationship holds for the nuclear magnetization of all regions in the sample, all the nuclear magnetization gathers on the y ′ axis at this time, and as a result, a large NMR signal is obtained.

As described above, by first applying a 90 ° pulse in the x′-axis direction and then applying a 180 ° pulse in the y′-axis direction, as shown in FIG. Reverses in the x'y 'plane. The compensation function is satisfactorily exhibited by the reversal of the nuclear magnetization. For example, the positions of P and Q have shifted to positions above or below the x'y 'plane due to (a) non-uniformity of the magnetic field and (b) non-uniformity of the excitation pulse intensity irradiated by the RF coil. Even in this case, the phase shift is compensated by reversing the nuclear magnetization in the x′y ′ plane.
As described above, after 2τ time, the magnetization vector converges on the “positive direction” of the Y axis, and an echo signal having a large amplitude is observed.

Second Pulse Sequence Further, in (c) above, the magnetization vector is irradiated with a 180 ° pulse from the outside in the “Y-axis direction” after 3τ time, and converged again on the “positive direction” of the Y-axis. An echo signal having a large amplitude is observed after 4τ time. Further, irradiation with 180 ° pulses is continued at the same 2τ interval. During this time, the peak intensity of the even-numbered echo signal E of 2τ, 4τ, 6τ,... Is extracted and fitted with an exponential function, so that the T ₂ (lateral) relaxation time constant by the CPMG method can be derived well. (FIG. 4 # 103-1t).

Deriving the T ₂ relaxation time constant (ii) the T ₂ relaxation time constant can be accurately determined by utilizing the spin echo method described above with reference to FIG. The intensity SSE of the echo signal when using the spin echo is expressed by the following equation (A) in the case of TR >> TE.

(Equation 1)
SSE = A × ρ (x, y, z) × {1-exp (−TR / T1)} × exp (−TE / T2) Expression (A)

  In the above formula (A), ρ is the density distribution of the target nuclide as a function of the position (x, y, z), TR is the 90 ° pulse repetition time (about 100 ms to 10 s), TE is the echo time (2τ, 1 ms) A is a constant representing the RF coil detection sensitivity and device characteristics such as an amplifier.

Therefore, by fitting a plurality of echo signal groups (2τ, 4τ, 6τ,...) On the acquired T ₂ attenuation curve with an exponential function, the T ₂ relaxation time constant is obtained from the above equation (A). Can be sought.

(Iii) Derivation of water content The water content is derived from the T ₂ relaxation time constant. The amount of water in the sample and the T ₂ relaxation time constant have a positive correlation, and the T ₂ relaxation time constant increases as the amount of water increases. Since this correlation varies depending on the type and form of the sample, an index can be created for a sample of the same type as the sample to be measured whose moisture content is known in advance. That is, the relationship between the moisture content and the T ₂ relaxation time constant is measured for a plurality of standard samples with known moisture content, and an index (calibration curve or calibration table) representing this relationship is obtained in advance. By referring to the index created in this way, the amount of water in the sample can be derived from the measured T ₂ relaxation time constant (# 104-1w in FIG. 4).

In the above example, the T ₂ relaxation time constant is used for the derivation of the moisture amount. However, as described above, the moisture amount and the intensity SSE of the echo signal E are positively correlated. The intensity of the echo signal E can also be used for deriving the amount of water.
This situation will be described based on the drawings. FIG. 7A shows an NMR signal when water is present (the amount of water is large), and FIG. 7B shows no water (the amount of water is small). The NMR signal in the case is shown. The eco part E is indicated by an arrow in the drawing. As a result, it can be seen that the intensity of the eco-signal E can also be used to specify the amount of water.

External device for CV measurement The external device for CV measurement 53 includes a CV measurement unit 53b and a CV information analysis unit 53c as functional parts.
The CV measurement unit 53b acquires a CV characteristic by performing a potential sweep for acquiring the CV characteristic between the anode side electrode catalyst layer 34b and the internal electrode 40 via the CV measurement lead wire 53a.
The CV information analysis unit 53c derives the hydrogen peroxide concentration of the cell model 30 from the CV characteristics measured by the CV measurement unit 53b.
This will be further described below.

CV measuring unit CV is a method of measuring a response current by linearly sweeping an electrode potential.
In the present embodiment, the reference potential portion is the anode-side electrode catalyst layer 34 b of the cell model 30, and a measurement potential is applied to the internal electrode 40. The CV measurement unit 53b performs a potential sweep operation and a response current measurement (# 102-2 in FIG. 4).
Normally, the potential sweep sweeps from the potential 0 to the positive side, and stops increasing the potential when the potential has reached a predetermined potential. After that, the potential is swept to a predetermined negative potential and recovered to rise to zero. Here, the predetermined potential is a potential at which the current becomes substantially constant with respect to the increase or decrease of the potential.

FIG. 8 shows a measurement result called a CV curve (a kind of CV characteristic).
This figure shows CV curves when the hydrogen peroxide concentration is changed to 5 ppm, 10 ppm, and 20 ppm, respectively.

CV Information Analysis Unit As can be seen from FIG. 8, the current in the stable region in the CV curve increases as the hydrogen peroxide concentration in the PEM 31 increases. That is, the hydrogen peroxide concentration and the current at a specific potential have a positive correlation. For example, the measurement can be performed satisfactorily by obtaining a calibration line in advance using a current of 1.3 V in FIG. 8 as an estimation index of the hydrogen peroxide concentration. The electric current [mA] at a potential of 1.3 V is y, and the hydrogen peroxide concentration [ppm] is x.
Therefore, the CV information analysis unit 52c specifically obtains the current of the specific potential located in the current stable region from the CV characteristic measured by the CV measurement unit 52b (# 103-2 in FIG. 4), and the hydrogen peroxide concentration Is derived (# 44-2 in FIG. 4).

NMR Measurement / CV Measurement Simultaneous measurement of NMR measurement and CV measurement using the measurement system described above is performed according to FIG.
# 101
The cell model 30 is installed in the magnetic field region of the permanent magnet 1, and the NMR measurement lead 52 a is connected to the NMR measurement external device 52 and the CV measurement lead 53 a is connected to the CV measurement external device 53.
Since the cell model 30 includes the casing 33 for electromagnetic wave shielding, NMR measurement and CV measurement can be performed in a state where the influence of external electromagnetic waves is reduced and a static magnetic field H is applied. .

NMR measurement is performed in the following sequence.
# 102-1
A high frequency pulse for excitation (specifically, a pulse sequence suitable for measurement purposes) is applied to the PEM 31 using a small RF coil 37.
An NMR signal (echo signal) is acquired.
The operation of Step 102-1 is executed by the NMR measurement unit 52b provided in the NMR measurement external device 52.

# 103-1f, # 103-1t
A frequency shift is derived for current measurement from the NMR signal obtained by # 102-1. On the other hand, for moisture measurement, a T ₂ relaxation time constant is derived.
# 104-1i, # 104-1w
Further, the current is derived from the derived frequency shift, and the moisture content is derived from the T ₂ relaxation time constant.
These operations are executed by the NMR information analysis unit 52c provided in the NMR measurement external device 52.

CV measurement is performed in the following sequence.
# 102-2
A potential sweep is performed between the anode-side electrode layer 34b and the internal electrode 40, current detection is performed, and CV characteristics (CV curve) are measured.
The operation of Step 102-2 is executed by the CV measurement unit 53b provided in the CV measurement external device 53.

# 103-2, # 104-2
A current corresponding to a specific potential is obtained from the CV characteristic obtained in step 102-2, and the hydrogen peroxide concentration is derived.
This operation is executed by the CV information analysis unit 53c provided in the external device 53 for CV measurement.

# 105
The derived result can be output as appropriate and is stored in a predetermined storage unit (not shown).

As described above, in the measurement system 100 according to the present application,
An NMR measurement step of acquiring an NMR signal by the NMR measurement unit 52b;
A CV measurement step of acquiring CV characteristics by the CV measurement unit 53b,
An NMR information analysis step of deriving one or more of the current and water content of the cell model 30 from the NMR signal acquired by the NMR measurement unit 52b by the NMR information analysis unit 52c;
A CV information analysis step of deriving the hydrogen peroxide concentration of the cell model from the CV characteristic measured by the CV measurement unit 53b by the CV information analysis unit 53c,
Simultaneous measurement of the current and water content of the cell model 30 and the hydrogen peroxide concentration of the cell model 30 is executed.
Furthermore, the simultaneous measurement method can be repeated sequentially.

  Further, NMR measurement and CV measurement are performed in a battery power generation state in which an electrical load is applied between the electrode catalyst layers 34 and fuel gas is supplied from the fuel gas flow passage 42 and oxidizing gas is supplied from the oxidizing gas flow passage 43. be able to.

The above is the basic structure for executing NMR measurement and CV measurement in the measurement system 100 of the present application.
In the measurement system 100 of the present application, since the NMR measurement and the CV measurement are performed simultaneously, the cell model 30 is disposed and used in the permanent magnet 1 that forms the static magnetic field H. Further, in the NMR measurement and the CV measurement, the electrode catalyst layer 34, the internal electrode 40, the small RF coil 37, the NMR measurement lead 38, and the CV measurement lead 39 arranged in the electromagnetic wave shielding casing 33 are used. As a result, mutual interference between both measurement systems becomes a problem.

In the system 100, measures are taken to reduce such mutual interference.
The problems newly found by the inventors as such mutual interference were the following two points. Hereinafter, countermeasures (structural countermeasures) for each problem will be described in order.

Elimination of noise on NMR signal due to CV measurement As shown in FIGS. 2 and 3, a penetrating EMI filter 41 is provided in the lead penetration portion of the electromagnetic wave shielding casing 33 in the lead wire 53 a for CV measurement. . The penetration EMI filter 41 was a cutoff filter (bandwidth: several MHz, cutoff rate: 40 dB) having an NMR signal of 44 MHz as a center frequency. The electromagnetic wave shielding casing 33 is used as a filter ground for the penetrating EMI filter 41. The cutoff filter is a kind of attenuation filter.
As a result of investigating the effectiveness of the filter 41, in the NMR signal obtained by NMR measurement, the noise intensity (standard deviation) of the noise part could be reduced to about ¼ compared with the case where no filter was provided. . Here, the noise part is a noise part that appears after elapse of time from the echo signal E in the NMR signal shown in the upper part of FIG. This noise intensity was comparable to the case where CV measurement was not performed simultaneously (reference). As a result, it was proved effective in simultaneous measurement.

Removal of minute irregularities appearing in CV curve in static magnetic field As shown in FIGS. 2 and 3, PEFC 32 arranged in the housing 33 includes PEM 31, electrode catalyst layers 34 on both surfaces, GDL 35 on both sides, The cell structure 45 is formed by integrating the internal electrode 40 and the small RF coil 37. The cell structure 45 becomes a fixed system of the device together with the casing 33 described so far.
In the cell model 30 according to the present application, the CV measurement lead wire portion 39 located in the housing 33 is fixed to the cell structure 45. Specifically, as shown in FIG. 3, the cell structure 45 and the housing 33 are connected to each other, and a plurality of CV measurement conductor portions 39 (three conductors connected to the internal electrode 40 in the example shown in the drawing) are provided. ).

  FIG. 9 shows a CV curve when the CV measurement lead wire portion 39 is not fixed and when it is fixed. FIG. 9A is a CV curve when the conducting wire is not fixed, and FIG. 9B is a CV curve when the conducting wire is fixed. When not fixed, it can be seen that minute irregularities appearing on the CV curve are eliminated by fixing.

[Another embodiment]
A In the above embodiment, both the current and the water content are determined based on the NMR measurement as the measurement target of the measurement system, but either one may be used.
B In addition, when NMR measurement is performed, a gradient magnetic field application unit that applies a gradient magnetic field to the sample is provided, and the mobility of moisture in the sample is derived based on the NMR signal acquired by the small RF coil. A mobility analysis unit may be provided. In this configuration, the small RF coil applies the excitation oscillating magnetic field to the sample, acquires NMR signals corresponding to the excitation oscillating magnetic field and the gradient magnetic field, and the mobility analyzer responds to the different gradient magnetic fields. Based on the obtained NMR signal, it can be configured to derive the mobility of a specific portion of the sample.
C In the above embodiment, in the CV measurement, the potential sweep between the electrodes is executed in both the positive side and the negative side, and a so-called CV curve is obtained, and then the hydrogen peroxide concentration is determined based on the current of the specific potential. However, if it is determined in advance that the current of the specific potential in the operation of raising the potential sweep is used for deriving the hydrogen peroxide concentration as the specific potential, the potential sweep is from 0 potential to the specific potential. The hydrogen peroxide concentration may be obtained from the current flowing at a specific potential.
D Furthermore, in the case of the configuration of the present application, since the local hydrogen peroxide concentration can be measured, it may be output as the hydrogen peroxide amount of the entire film.
F In the above-described embodiment, the position of the CV measurement lead wire portion 39 is fixed by the hook 46. However, any fixing method may be used, and any fixing means such as fixing by adhesion or the like may be employed.

  As mentioned above, the measurement technique which can perform both NMR measurement and CV measurement simultaneously and accurately was able to be established.

1 Permanent magnet 30 Cell model 31 Solid polymer electrolyte membrane (PEM)
32 Polymer electrolyte fuel cell (PEFC)
33 Housing 34 Electrode catalyst layer 36 Electronic load 37 Small RF coil 39 CV measurement conductor 40 Internal electrode 41 Filter 42 Fuel gas flow path 43 Oxidative gas flow path 50 External device 52 NMR measurement external device 52 a For NMR measurement Conductor 52 b NMR measurement unit 52 c NMR information analysis unit 53 CV measurement external device 53 a CV measurement lead 53 b CV measurement unit 53 c CV information analysis unit 100 Measurement system

Claims (11)

A cell model that simulates the operating state of a polymer electrolyte fuel cell,
A solid polymer electrolyte membrane;
An anode-side electrode catalyst layer provided on the surface of the solid polymer electrolyte membrane and a cathode-side electrode catalyst layer provided on the back surface;
A fuel gas flow passage for supplying fuel gas from the anode side electrode catalyst layer side to the solid polymer electrolyte membrane;
An oxidizing gas flow passage for supplying an oxidizing gas from the cathode side electrode catalyst layer side to the solid polymer electrolyte membrane,
An internal electrode provided inside the solid polymer electrolyte membrane;
A small RF coil that applies an oscillating magnetic field for excitation to the solid polymer electrolyte membrane and acquires a nuclear magnetic resonance signal generated in the solid polymer electrolyte membrane,
In a state where the cell structure including the solid polymer electrolyte membrane, the two electrode catalyst layers, the internal electrode and the small RF coil is accommodated in a static magnetic field,
NMR measurement conductors that electrically connect each of the pair of terminals of the small RF coil to an NMR measurement external device outside the static magnetic field;
A conductor for CV measurement that electrically connects each of the anode-side electrode catalyst layer and the internal electrode to an external device for CV measurement outside a static magnetic field,
The CV measurement lead is provided with a filter for attenuating the frequency signal of the nuclear magnetic resonance signal,
A cell model in which at least a CV measurement lead portion located in the static magnetic field is fixed.   2. The cell according to claim 1, further comprising: a casing that shields the cell structure from the outside in a state where the static magnetic field is applied to the cell structure, and a penetrating EMI filter as the filter. model.   The cell model according to claim 1 or 2, wherein the position of the CV measurement lead wire to be fixed is fixed to the cell structure and fixed in the static magnetic field.   The cell model according to any one of claims 1 to 3, wherein the internal electrodes and the small RF coils are dispersedly arranged in the spreading direction of the solid polymer electrolyte membrane.   The cell model according to any one of claims 1 to 4, wherein the internal electrodes and the small RF coils are each distributed and arranged at least in the fuel gas flow direction. The cell model according to any one of claims 1 to 5,
A static magnetic field application device that applies a static magnetic field to the solid polymer electrolyte membrane in a state in which the cell model is accommodated therein,
An NMR measurement unit that applies an oscillating magnetic field for excitation to the solid polymer electrolyte membrane through the NMR measurement lead and the small RF coil, and acquires a nuclear magnetic resonance signal generated in the solid polymer electrolyte membrane; ,
A CV measurement unit that acquires a CV signal by performing a potential sweep for CV characteristic acquisition between the anode-side electrode catalyst layer and the internal electrode via the CV measurement lead;
A measurement system in which CV characteristics can be measured by the CV measurement unit in a state where a static magnetic field is applied to the solid polymer electrolyte membrane by the static magnetic field application device. From the nuclear magnetic resonance signal acquired by the NMR measurement unit, an NMR information analysis unit for deriving one or more of the current state and moisture state of the cell model;
The measurement system according to claim 6, further comprising: a CV information analysis unit that derives a hydrogen peroxide state of the cell model from the CV characteristics measured by the CV measurement unit.   The measurement system according to claim 6 or 7, wherein the NMR measurement unit and the CV measurement unit work simultaneously to sequentially execute simultaneous measurement for simultaneously executing NMR measurement and CV measurement. Using the measurement system according to claim 7,
NMR measurement step of acquiring the nuclear magnetic resonance signal by the NMR measurement unit,
A CV measurement step of measuring the CV characteristics by the CV measurement unit;
From the nuclear magnetic resonance signal acquired by the NMR measurement unit, an NMR information analysis step of deriving any one or more of the current state and moisture state of the cell model by the NMR information analysis unit,
From the CV characteristics measured by the CV measurement unit, a CV information analysis step of deriving the hydrogen peroxide state of the cell model by the CV information analysis unit is performed.
A simultaneous measurement method for executing simultaneous measurement of at least one of a current state and a moisture state of a cell model and a hydrogen peroxide state of the cell model.   A sequential simultaneous measurement method for sequentially repeating the simultaneous measurement method according to claim 9. 10. An NMR measurement and a CV measurement are performed in a battery power generation state in which an electronic load is applied between the electrode catalyst layers and fuel gas is supplied from the fuel gas flow passage and oxidizing gas is supplied from the oxidizing gas flow passage. Or the simultaneous measurement method of 10.